Structure-based virtual screening utilizing the approved drugs is an intriguing and laudable approach to excavate novel alternatives for different indications based on the vast amount of reported experimental data.Vir...Structure-based virtual screening utilizing the approved drugs is an intriguing and laudable approach to excavate novel alternatives for different indications based on the vast amount of reported experimental data.Virus superfamily 1 helicase could resolve hydrogen bonds between base pairs and participate in nucleic acid replication and has emerged as a potential target for managing virus infection.Nonetheless,current drug exploitation targeting viral helicases is still in infancy.This work establishes an intelligent multi-computational screening programme to screen potential inhibitors targeting tobacco mosaic virus(TMV)helicase using Food and Drug Administration(FDA)-approved commercially available molecule library.The ranked top 6 hits were further validated by root mean square deviations/fluctuations(RMSD/F),molecular mechanics Poisson Boltzmann surface area(MM-PBSA),density functional theory(DFT)calculations,and bioactivity evaluation.Encouragingly,lumacaftor(ΔE_(total)=-29.0kcal/mol,K_(d)=0.22μmol/L,half maximal inhibitory concentration(IC_(50))=162.5μmol/L)displayed superior binding strength and enzyme inhibition against TMV helicase compared to ningnanmycin(K_(d)=9.35μmol/L,IC_(50)>200μmol/L).Therefore,lumacaftor may be able to inhibit TMV replication by binding to helicase and interfering with its biofunctionability.Besides,the lumacaftor-helicase binding mode changes from H-bonding/electrostatic interactions to hydrophobic interactions in trajectory analysis.Overall,current findings suggest this state-of-the-art stratagem is fruitful and has the potential to be engaged in rapid mining of other target inhibitors for disease treatment.展开更多
BACKGROUND Pancreatic cancer(PC)remains one of the most aggressive malignancies,is charac-terized by rapid progression and high metastatic potential,and is the fourth leading cause of cancer-related mortality worldwid...BACKGROUND Pancreatic cancer(PC)remains one of the most aggressive malignancies,is charac-terized by rapid progression and high metastatic potential,and is the fourth leading cause of cancer-related mortality worldwide.The incidence and mortality rates of PC continue to rise annually.Despite advances in imaging technologies and treatment strategies over the past two decades,the 5-year survival rate for patients with PC remains low,at approximately 13%.Patients with advanced PC still experience dismal outcomes,primarily due to the tumor's aggressiveness and high metastatic capacity.Thus,there is an urgent need to identify reliable mole-cular biomarkers and therapeutic targets to improve the prognosis of patients with PC.We comprehensively investigated the expression pattern and functional signi-ficance of DDX10 in PC using a multi-omics integrative approach.We performed bioinformatics analyses of datasets from The Cancer Genome Atlas and Gene Expression Omnibus,tissue microarray-based immunohistochemistry,and a series of in vitro functional assays to assess cellular proliferation,migration,inva-sion,and apoptosis.Additionally,transcriptomic and proteomic analyses were integrated to delineate the molecular regulatory networks that mediate the aggressive phenotype of PC.RESULTS DDX10 was found to be significantly overexpressed at both the mRNA and protein levels in PC tissues compared with adjacent non-tumor tissues.Silencing DDX10 in vitro led to marked inhibition of PC cell proliferation,migration,and invasion,accompanied by enhanced apoptosis.Integrated RNA sequencing,proteomic profiling,and western blot validation revealed that DDX10 modulates key oncogenes including RRM2,LIG1,CDK6,and ITGA2.Notably,ectopic RRM2 overexpression partially rescued the growth-suppressive effects induced by DDX10 knockdown in PANC-1 cells,and high DDX10 expression is associated with poor overall survival in patients with PC.CONCLUSION Collectively,our findings indicate that DDX10 promotes PC cell proliferation primarily by upregulating RRM2,thus highlighting its potential as a promising therapeutic target in PC.展开更多
Background Liver ischemia/reperfusion(I/R)injury is usually caused by hepatic inflow occlusion during liver surgery,and is frequently observed during war wounds and trauma.Hepatocyte ferroptosis plays a critical role ...Background Liver ischemia/reperfusion(I/R)injury is usually caused by hepatic inflow occlusion during liver surgery,and is frequently observed during war wounds and trauma.Hepatocyte ferroptosis plays a critical role in liver I/R injury,however,it remains unclear whether this process is controlled or regulated by members of the DEAD/DExH-box helicase(DDX/DHX)family.Methods The expression of DDX/DHX family members during liver I/R injury was screened using transcriptome analysis.Hepatocyte-specific Dhx58 knockout mice were constructed,and a partial liver I/R operation was performed.Single-cell RNA sequencing(scRNA-seq)in the liver post I/R suggested enhanced ferroptosis by Dhx58hep−/−.The mRNAs and proteins associated with DExH-box helicase 58(DHX58)were screened using RNA immunoprecipitation-sequencing(RIP-seq)and IP-mass spectrometry(IP-MS).Results Excessive production of reactive oxygen species(ROS)decreased the expression of the IFN-stimulated gene Dhx58 in hepatocytes and promoted hepatic ferroptosis,while treatment using IFN-αincreased DHX58 expression and prevented ferroptosis during liver I/R injury.Mechanistically,DHX58 with RNA-binding activity constitutively associates with the mRNA of glutathione peroxidase 4(GPX4),a central ferroptosis suppressor,and recruits the m6A reader YT521-B homology domain containing 2(YTHDC2)to promote the translation of Gpx4 mRNA in an m6A-dependent manner,thus enhancing GPX4 protein levels and preventing hepatic ferroptosis.Conclusions This study provides mechanistic evidence that IFN-αstimulates DHX58 to promote the translation of m6A-modified Gpx4 mRNA,suggesting the potential clinical application of IFN-αin the prevention of hepatic ferroptosis during liver I/R injury.展开更多
The ongoing outbreak of Coronavirus Disease 2019(COVID-19)has become a global public health emergency.SARScoronavirus-2(SARS-CoV-2),the causative pathogen of COVID-19,is a positive-sense single-stranded RNA virus belo...The ongoing outbreak of Coronavirus Disease 2019(COVID-19)has become a global public health emergency.SARScoronavirus-2(SARS-CoV-2),the causative pathogen of COVID-19,is a positive-sense single-stranded RNA virus belonging to the family Coronaviridae.For RNA viruses,virus-encoded RNA helicases have long been recognized to play pivotal roles during viral life cycles by facilitating the correct folding and replication of viral RNAs.Here,our studies show that SARS-CoV-2-encoded nonstructural protein 13(nsp13)possesses the nucleoside triphosphate hydrolase(NTPase)and RNA helicase activities that can hydrolyze all types of NTPs and unwind RNA helices dependently of the presence of NTP,and further characterize the biochemical characteristics of these two enzymatic activities associated with SARS-CoV-2 nsp13.Moreover,we found that some bismuth salts could effectively inhibit both the NTPase and RNA helicase activities of SARS-CoV-2 nsp13 in a dose-dependent manner.Thus,our findings demonstrate the NTPase and helicase activities of SARS-CoV-2 nsp13,which may play an important role in SARS-CoV-2 replication and serve as a target for antivirals.展开更多
Foot-and-mouth disease virus(FMDV)can infect domestic and wild cloven-hoofed animals.The non-structural protein 3D plays an important role in FMDV replication and pathogenesis.However,the interaction partners of 3D,an...Foot-and-mouth disease virus(FMDV)can infect domestic and wild cloven-hoofed animals.The non-structural protein 3D plays an important role in FMDV replication and pathogenesis.However,the interaction partners of 3D,and the effects of those interactions on FMDV replication,remain incompletely elucidated.In the present study,using the yeast two-hybrid system,we identified a porcine cell protein,DEAD-box RNA helicase 1(DDX1),which interacted with FMDV 3D.The DDX1-3D interaction was further confirmed by co-immunoprecipitation experiments and an indirect immunofluorescence assay(IFA)in porcine kidney 15(PK-15)cells.DDX1 was reported to either inhibit or facilitate viral replication and regulate host innate immune responses.However,the roles of DDX1 during FMDV infection remain unclear.Our results revealed that DDX1 inhibited FMDV replication in an ATPase/helicase activity-dependent manner.In addition,DDX1 stimulated IFN-p activation in FMDV-infected cells.Together,our results expand the body of knowledge regarding the role of DDX1 in FMDV infection.展开更多
Objective:Hepatocellular carcinoma(HCC),the main type of liver cancer,has a high morbidity and mortality,and a poor prognosis.RNA helicase DDX5,which acts as a transcriptional co-regulator,is overexpressed in most mal...Objective:Hepatocellular carcinoma(HCC),the main type of liver cancer,has a high morbidity and mortality,and a poor prognosis.RNA helicase DDX5,which acts as a transcriptional co-regulator,is overexpressed in most malignant tumors and promotes cancer cell growth.Heat shock protein 90(HSP90)is an important molecular chaperone in the conformational maturation and stabilization of numerous proteins involved in cell growth or survival.Methods:DDX5 m RNA and protein expression in surgically resected HCC tissues from 24 Asian patients were detected by quantitative real-time PCR and Western blot,respectively.The interaction of DDX5-HSP90 was determined by molecular docking,immunoprecipitation,and laser scanning confocal microscopy.The autophagy signal was detected by Western blot.The cell functions and signaling pathways of DDX5 were determined in 2 HCC cell lines.Two different murine HCC xenograft models were used to determine the function of DDX5 and the therapeutic effect of an HSP90 inhibitor.Results:HSP90 interacted directly with DDX5 and inhibited DDX5 protein degradation in the AMPK/ULK1-regulated autophagy pathway.The subsequent accumulation of DDX5 protein induced the malignant phenotype of HCC by activating theβ-catenin signaling pathway.The silencing of DDX5 or treatment with HSP90 inhibitor both blocked in vivo tumor growth in a murine HCC xenograft model.High levels of HSP90 and DDX5 protein were associated with poor prognoses.Conclusions:HSP90 interacted with DDX5 protein and subsequently protected DDX5 protein from AMPK/ULK1-regulated autophagic degradation.DDX5 and HSP90 are therefore potential therapeutic targets for HCC.展开更多
Recently emerged SARS-CoV-2 caused a major outbreak of coronavirus disease 2019(COVID-19)and instigated a widespread fear,threatening global health safety.To date,no licensed antiviral drugs or vaccines are available ...Recently emerged SARS-CoV-2 caused a major outbreak of coronavirus disease 2019(COVID-19)and instigated a widespread fear,threatening global health safety.To date,no licensed antiviral drugs or vaccines are available against COVID-19 although several clinical trials are under way to test possible therapies.During this urgent situation,computational drug discovery methods provide an alternative to tiresome high-throughput screening,particularly in the hit-to-lead-optimization stage.Identification of small molecules that specifically target viral replication apparatus has indicated the highest potential towards antiviral drug discovery.In this work,we present potential compounds that specifically target SARS-CoV-2 vital proteins,including the main protease,Nsp12 RNA polymerase and Nsp13 helicase.An integrative virtual screening and molecular dynamics simulations approach has facilitated the identification of potential binding modes and favourable molecular interaction profile of corresponding compounds.Moreover,the identification of structurally important binding site residues in conserved motifs located inside the active site highlights relative importance of ligand binding based on residual energy decomposition analysis.Although the current study lacks experimental validation,the structural information obtained from this computational study has paved way for the design of targeted inhibitors to combat COVID-19 outbreak.展开更多
Objective Bloom’s syndrome is an autosomal recessive disorder characterized by genomic instability and a predisposition to many cancers. Mutations of the BLM gene （encoding a BLM helicase） may form a structure of t...Objective Bloom’s syndrome is an autosomal recessive disorder characterized by genomic instability and a predisposition to many cancers. Mutations of the BLM gene （encoding a BLM helicase） may form a structure of the etiology of this disease. As a global pollutant, mercury poses a major threat to human health. The current study was conducted to elucidate the effects of Hg^2＋ on the structure and activity of BLM642‐1290 recombinant helicase, and to further explore the molecular mechanisms of mercury toxicity to the DNA helicase. Methods The effects of Hg^2＋ on biological activity and structure of BLM642‐1290 recombinant helicase were determined by fluorescence polarized, ultraviolet spectroscopic, and free‐phosphorus assay technologies, respectively. Results The helicase activity, the DNA‐binding activity, and the ATPase activity of BLM642‐1290 recombinant helicase were inhibited by Hg^2＋ treatment. The LMCT （ligand‐to‐metal charge transition） peaks of the helicase were enhanced with the increase of the Hg^2＋ level. The LMCT peaks of the same concentration of helicase gradually increased over time. Conclusions The biological activity of BLM642‐1290 recombinant helicase is inhibited by Hg^2＋ treatment. The conformation of the helicase is significantly altered by Hg^2＋ . There exist two binding sites between Hg^2＋ and the helicase, which are located in the amino acid residues 1063‐1066 and 940‐944 of the helicase, respectively.展开更多
The current therapeutic regimen to combat chronic hepatitis C is not optimal due to substantial side effects and the failure of a significant proportion of patients to achieve a sustained virological response. Recentl...The current therapeutic regimen to combat chronic hepatitis C is not optimal due to substantial side effects and the failure of a significant proportion of patients to achieve a sustained virological response. Recently developed direct-acting antivirals targeting hepatitis C virus (HCV) enzymes reportedly increase the virologic response to therapy but may lead to a selection of drug-resistant variants. Besides direct-acting antivirals, another promising class of HCV drugs in development include host targeting agents that are responsible for interfering with the host factors crucial for the viral life cycle. A family of host proteins known as DEAD-box RNA helicases, characterized by nine conserved motifs, is known to play an important role in RNA metabolism. Several members of this family such as DDX3, DDX5 and DDX6 have been shown to play a role in HCV replication and this review will summarize our current knowledge on their interaction with HCV. As chronic hepatitis C is one of the leading causes of hepatocellular carcinoma, the involvement of DEAD-box RNA helicases in the development of HCC will also be highlighted. Continuing research on the interaction of host DEAD-box proteins with HCV and the contribution to viral replication and pathogenesis could be the panacea for the development of novel therapeutics against HCV.展开更多
P68 RNA helicase is a prototypical DEAD box RNA helicase. The protein plays a very important role in early organ development and maturation. Consistent with the function of the protein in transcriptional regulation an...P68 RNA helicase is a prototypical DEAD box RNA helicase. The protein plays a very important role in early organ development and maturation. Consistent with the function of the protein in transcriptional regulation and pre-mRNA splicing, p68 was found to predominately localize in the cell nucleus. However, recent experiments demon- strate a transient cytoplasmic localization of the protein. We report here that p68 shuttles between the nucleus and the cytoplasm. The nucleocytoplasmic shuttling of p68 is mediated by two nuclear localization signal and two nuclear exporting signal sequence elements. Our experiments reveal that p68 shuttles via a classical RanGTPase-dependent pathway.展开更多
Objective To study the effect of fleroxacin （FLRX） on biological properties of Bloom （BLM） helicase catalytic core （BLM 642-2290 helicase） in vitro and the molecular mechanism of interaction between the two mol...Objective To study the effect of fleroxacin （FLRX） on biological properties of Bloom （BLM） helicase catalytic core （BLM 642-2290 helicase） in vitro and the molecular mechanism of interaction between the two molecules. Methods DNA-binding and unwinding activities of BLM 642-1290 helicase were assayed by fluorescence polarization and gel retardation assay under conditions that the helicase was subjected to different concentrations of FLRX. Effect of FLRX on helicase ATPase activity was analyzed by phosphorus-free assay based on a colorimetric estimation of ATP hydrolysis-produced inorganic phosphate. Molecular mechanism of interaction between the two molecules was assayed by ultraviolet and fluorescence spectra. Results The DNA unwinding and ATPase activities of BLM 642-1290 helicase were inhibited whereas the DNA-binding activity was promoted in vitro. A BLM-FLRX complex was formed through one binding site, electrostatic and hydrophobic interaction force. Moreover, the intrinsic fluorescence of the helicase was quenched by FLRX as a result of non-radioactive energy transfer. The biological activity of helicase was affected by FLRX, which may be through an allosteric mechanism and stabilization of enzyme conformation in low helicase activity state, disruption of the coupling of ATP hydrolysis to unwinding, and blocking helicase translocation on DNA strands. Conclusion FLRX may affect the biological activities and conformation of BLM 642-1290 helicase, and DNA helicase may be used as a promising drug target for some diseases.展开更多
RNA-remodeling proteins,including RNA helicases and chaperones,play vital roles in the remodeling of structured RNAs.During viral replication,viruses require RNA-remodeling proteins to facilitate proper folding and/or...RNA-remodeling proteins,including RNA helicases and chaperones,play vital roles in the remodeling of structured RNAs.During viral replication,viruses require RNA-remodeling proteins to facilitate proper folding and/or re-folding the viral RNA elements.Coxsackieviruses B3(CVB3)and Coxsackieviruses B5(CVB5),belonging to the genus Enterovirus in the family Picornaviridae,have been reported to cause various infectious diseases such as hand-foot-and-mouth disease,aseptic meningitis,and viral myocarditis.However,little is known about whether CVB3 and CVB5 encode any RNA remodeling proteins.In this study,we showed that 2C proteins of CVB3 and CVB5 contained the conserved SF3 helicase A,B,and C motifs,and functioned not only as RNA helicase that unwound RNA helix bidirectionally in an NTP-dependent manner,but also as RNA chaperone that remodeled structured RNAs and facilitated RNA strand annealing independently of NTP.In addition,we determined that the NTPase activity and RNA helicase activity of 2C proteins of CVB3 and CVB5 were dependent on the presence of divalent metallic ions.Our findings demonstrate that 2C proteins of CVBs possess RNA-remodeling activity and underline the functional importance of 2C protein in the life cycle of CVBs.展开更多
Flaviviruses are positive-sense RNA viruses, and many are important human pathogens. Nonstructural protein 2B and 3 of the flaviviruses(NS2BNS3) form an endoplasmic reticulum(ER) membrane-associated hetero-dimeric com...Flaviviruses are positive-sense RNA viruses, and many are important human pathogens. Nonstructural protein 2B and 3 of the flaviviruses(NS2BNS3) form an endoplasmic reticulum(ER) membrane-associated hetero-dimeric complex through the NS2B transmembrane region. The NS2BNS3 complex is multifunctional. The N-terminal region of NS3, and its cofactor NS2B fold into a protease that is responsible for viral polyprotein processing, and the C-terminal domain of NS3 possesses NTPase/RNA helicase activities and is involved in viral RNA replication and virus particle formation. In addition, NS2BNS3 complex has also been shown to modulate viral pathogenesis and the host immune response. Because of the essential functions that the NS2BNS3 complex plays in the flavivirus life cycle, it is an attractive target for antiviral development. This review focuses on the recent biochemical and structural advances of NS2BNS3 and provides a brief update on the current status of drug development targeting this viral protein complex.展开更多
RecQ is a highly conserved helicase necessary for maintaining genome stability in all organisms. Genome comparison showed that a homologue of RecQ in Deinococcus radiodurans designated as DR1289 is a member of RecQ fa...RecQ is a highly conserved helicase necessary for maintaining genome stability in all organisms. Genome comparison showed that a homologue of RecQ in Deinococcus radiodurans designated as DR1289 is a member of RecQ family with unusual domain arrangement: a helicase domain, an RecQ C-terminal domain, and surprisingly three HRDC domain repeats, whose func-tion, however, remains obscure currently. Using an insertion deletion, we discovered that the DRRecQ mutation causes an increase in gamma radiation, hydroxyurea and mitomycine C and UV sensitivity. Using the shuttle plasmid pRADK, we complemented various domains of the D. radiodurans RecQ (DRRecQ) to the mutant in vivo. Results suggested that both the helicase and helicase-and-RNase-D-C-terminal (HRDC) domains are essential for complementing several phenotypes. The complementation and biochemical function of DRRecQ variants with different domains truncated in vitro suggested that both the helicase and three HRDC domains are necessary for RecQ functions in D. radiodurans, while three HRDC domains have a synergistic effect on the whole function. Our finding leads to the hypothesis that the RecF recombination pathway is likely a primary path of double strand break repair in this well-known radioresistant organism.展开更多
Grapevine growing areas are increasingly affected by drought,which has greatly limited global wine production and quality.DEAD-box is one of the largest subfamilies of the RNA helicase family,and its members play key ...Grapevine growing areas are increasingly affected by drought,which has greatly limited global wine production and quality.DEAD-box is one of the largest subfamilies of the RNA helicase family,and its members play key roles in the growth and development of plants and their stress responses.Previous studies have shown the potential of DEAD-box genes in the drought stress responses of Arabidopsis and tomato,rice,and other crop species.However,information about DEAD-box genes in grapevine remains limited.In this report,a total of 40 DEAD-box genes were identified in grapevine and their protein sequence characteristics and gene structures were analyzed.By comparing the expression profiles of VviDEADRHs in response to drought stress in different grapevine varieties,nine candidate genes(VviDEADRH10c,-13,-22,-25a,-25b,-33,-34,-36,and-39)were screened based on expression profiling data.Combined with qRTPCR results,Vvi DEADRH25a was selected for functional verification.Heterologous overexpression of Vvi DEADRH25a in Arabidopsis showed the transgenic plants were more sensitive to drought stress than the control.Both electrolyte permeability and malondialdehyde content were significantly increased in transgenic plants,whereas the chlorophyll content and superoxide dismutase(SOD),peroxidase(POD),catalase(CAT),and ascorbate peroxidase(APX)enzyme activities were significantly decreased.Furthermore,VviDEADRH25a-overexpressing plants showed down-regulated expression levels of several drought stress-related marker genes,namely At COR15a,At RD29A,At ERD15,and At P5CS1,which indicated that they participated in the drought stress response.In summary,this study provides new insights into the structure,evolution,and participation of DEAD-box RNA helicase genes in the response to drought stress in grapevines.展开更多
OBJECTIVE To evaluate if RNA helicase DDX20,highly expressed in triple negative breast cancer(TNBC)cells,could serve as a surrogate marker for simvastatin treatment response.METHODS We first assessed correlation betwe...OBJECTIVE To evaluate if RNA helicase DDX20,highly expressed in triple negative breast cancer(TNBC)cells,could serve as a surrogate marker for simvastatin treatment response.METHODS We first assessed correlation between 17 mevalonate pathway-related genes and expression of DDX20 in a cohort of 1325 breast cancer tumors.TNBC cells,MDA-MB-231,were then treated with simvastatin and mevalonate pathway intermediates to assess the alteration in DDX20 expression.In the mouse model,MDA-MB-231 cells were injected to tail veins of mice,groups of 8mice each were injected intraperioneally with vehicle or simvastatin 25mg·kg-1 3times a week for 6weeks.The number of metastatic colonies formed was quantified and immunohistochemical(IHC)staining of DDX20 was carried out in the lung tissues.RESULTS Among the 17 genes evaluated,positive correlation with DDX20 expression was observed in eight of them,with HMGCR having the highest correlation.Our in vitro experiments show exposure of breast cancer cells to simvastatin lead to a Rho-dependent decrease in gene expression of DDX20,leading to decreased tumor proliferation in a mevalonate pathway-dependent manner.Conversely,ectopic overexpression of DDX20 significantly abrogated the anti-metastatic activity of simvastatin.A similar observation is seen in the mouse model,where simvastatin-injected mice show significantly fewer visible lung metastases compared to placebo-fed mice.IHC staining on these lung tissues showed decreased DDX20 expression in simvastatin-injected group,corroborating our observations in vitro.CONCLUSION DDX20 is a potential surrogate marker for simvastatin treatment response in breast cancer and a long term implication of our findings is the possibility of an effective combinatorial therapeutic intervention using statins(to suppress DDX20 gene expression)and a suitable firstline agent″for the kill″of invasive breast cancer.展开更多
RecQ5β is an essential DNA helicase in humans, playing important roles in DNA replication, repair, recombination and transcription. The unwinding activity and substrate specificity of RecQ5β is still elusive. Here, ...RecQ5β is an essential DNA helicase in humans, playing important roles in DNA replication, repair, recombination and transcription. The unwinding activity and substrate specificity of RecQ5β is still elusive. Here, we used stopped-flow kinetic method to measure the unwinding and dissociation kinetics of RecQ5β with several kinds of DNA substrates, and found that RecQ5β could well unwind ss/ds DNA, forked DNA and Holiday junction, but was compromised in unwinding blunt DNA and G-quadruplex. Rec5β has the preferred unwinding specificity for certain DNA substrates containing the junction point, which may improve the binding affinity and unwinding activity of RecQ5β. Moreover, from a comparison with the truncated RecQ5β～（1-467）, we discovered that the C-terminal domain might strongly influence the unwinding activity and binding affinity of RecQ5β. These results may shed light on the physiological functions and working mechanisms of RecQ5β helicase.展开更多
A significant number of mycoviruses have been identified that are related to plant viruses,but their evolutionary relationships are largely unexplored.A fusarivirus,Rhizoctonia solani fusarivirus 4(RsFV4),was identifi...A significant number of mycoviruses have been identified that are related to plant viruses,but their evolutionary relationships are largely unexplored.A fusarivirus,Rhizoctonia solani fusarivirus 4(RsFV4),was identified in phytopathogenic fungus Rhizoctonia solani(R.solani)strain XY74 co-infected by an alphaendornavirus.RsFV4 had a genome of 10,833 nt(excluding the poly-A tail),and consisted of four non-overlapping open reading frames(ORFs).ORF1 encodes an 825 aa protein containing a conserved helicase domain(Hel1).ORF3 encodes 1550 aa protein with two conserved domains,namely an RNA-dependent RNA polymerase(RdRp)and another helicase(Hel2).The ORF2 and ORF4 likely encode two hypothetical proteins(520 and 542 aa)with unknown functions.The phylogenetic analysis based on Hel2 and RdRp suggest that RsFV4 was positioned within the fusarivirus group,but formed an independent branch with three previously reported fusariviruses of R.solani.Notably,the Hel1 and its relatives were phylogenetically closer to helicases of potyviruses and hypoviruses than fusariviruses,suggesting fusarivirus Hel1 formed an evolutionary link between these three virus groups.This finding provides evidence of the occurrence of a horizontal gene transfer or recombination event between mycoviruses and plant viruses or between mycoviruses.Our findings are likely to enhance the understanding of virus evolution and diversity.展开更多
基金financially supported by National Natural Science Foundation of China(Nos.32372610,U23A20201,32160661,32202359)National Key Research and Development Program of China(No.2022YFD1700300)the Central Government Guides Local Science and Technology Development Fund Projects(Nos.[Qiankehezhongyindi(2023)001]and[Qiankehezhongyindi[2024]007])。
文摘Structure-based virtual screening utilizing the approved drugs is an intriguing and laudable approach to excavate novel alternatives for different indications based on the vast amount of reported experimental data.Virus superfamily 1 helicase could resolve hydrogen bonds between base pairs and participate in nucleic acid replication and has emerged as a potential target for managing virus infection.Nonetheless,current drug exploitation targeting viral helicases is still in infancy.This work establishes an intelligent multi-computational screening programme to screen potential inhibitors targeting tobacco mosaic virus(TMV)helicase using Food and Drug Administration(FDA)-approved commercially available molecule library.The ranked top 6 hits were further validated by root mean square deviations/fluctuations(RMSD/F),molecular mechanics Poisson Boltzmann surface area(MM-PBSA),density functional theory(DFT)calculations,and bioactivity evaluation.Encouragingly,lumacaftor(ΔE_(total)=-29.0kcal/mol,K_(d)=0.22μmol/L,half maximal inhibitory concentration(IC_(50))=162.5μmol/L)displayed superior binding strength and enzyme inhibition against TMV helicase compared to ningnanmycin(K_(d)=9.35μmol/L,IC_(50)>200μmol/L).Therefore,lumacaftor may be able to inhibit TMV replication by binding to helicase and interfering with its biofunctionability.Besides,the lumacaftor-helicase binding mode changes from H-bonding/electrostatic interactions to hydrophobic interactions in trajectory analysis.Overall,current findings suggest this state-of-the-art stratagem is fruitful and has the potential to be engaged in rapid mining of other target inhibitors for disease treatment.
基金Supported by National Natural Science Foundation of China,No.82160588Health Commission of Gansu Province,No.GSWSKY2021-032+1 种基金Natural Science Foundation of Gansu Province,No.24JRRA585Gansu Provincial Hospital Science and Technology Innovation Platform Fund Project,No.21GSSYB-23.
文摘BACKGROUND Pancreatic cancer(PC)remains one of the most aggressive malignancies,is charac-terized by rapid progression and high metastatic potential,and is the fourth leading cause of cancer-related mortality worldwide.The incidence and mortality rates of PC continue to rise annually.Despite advances in imaging technologies and treatment strategies over the past two decades,the 5-year survival rate for patients with PC remains low,at approximately 13%.Patients with advanced PC still experience dismal outcomes,primarily due to the tumor's aggressiveness and high metastatic capacity.Thus,there is an urgent need to identify reliable mole-cular biomarkers and therapeutic targets to improve the prognosis of patients with PC.We comprehensively investigated the expression pattern and functional signi-ficance of DDX10 in PC using a multi-omics integrative approach.We performed bioinformatics analyses of datasets from The Cancer Genome Atlas and Gene Expression Omnibus,tissue microarray-based immunohistochemistry,and a series of in vitro functional assays to assess cellular proliferation,migration,inva-sion,and apoptosis.Additionally,transcriptomic and proteomic analyses were integrated to delineate the molecular regulatory networks that mediate the aggressive phenotype of PC.RESULTS DDX10 was found to be significantly overexpressed at both the mRNA and protein levels in PC tissues compared with adjacent non-tumor tissues.Silencing DDX10 in vitro led to marked inhibition of PC cell proliferation,migration,and invasion,accompanied by enhanced apoptosis.Integrated RNA sequencing,proteomic profiling,and western blot validation revealed that DDX10 modulates key oncogenes including RRM2,LIG1,CDK6,and ITGA2.Notably,ectopic RRM2 overexpression partially rescued the growth-suppressive effects induced by DDX10 knockdown in PANC-1 cells,and high DDX10 expression is associated with poor overall survival in patients with PC.CONCLUSION Collectively,our findings indicate that DDX10 promotes PC cell proliferation primarily by upregulating RRM2,thus highlighting its potential as a promising therapeutic target in PC.
基金National Key Research and Development Program of China(2023YFC2505900)National Natural Science Foundation of China(92269204,82171755,92369106,82171749,82171811,82073184)+1 种基金Military Outstanding Youth Program(2020QN06119,01-SWK JYCJJ07,23SWAQ53)Program of Leading Talents in Shanghai,and Shanghai Shuguang Program(20SG39)。
文摘Background Liver ischemia/reperfusion(I/R)injury is usually caused by hepatic inflow occlusion during liver surgery,and is frequently observed during war wounds and trauma.Hepatocyte ferroptosis plays a critical role in liver I/R injury,however,it remains unclear whether this process is controlled or regulated by members of the DEAD/DExH-box helicase(DDX/DHX)family.Methods The expression of DDX/DHX family members during liver I/R injury was screened using transcriptome analysis.Hepatocyte-specific Dhx58 knockout mice were constructed,and a partial liver I/R operation was performed.Single-cell RNA sequencing(scRNA-seq)in the liver post I/R suggested enhanced ferroptosis by Dhx58hep−/−.The mRNAs and proteins associated with DExH-box helicase 58(DHX58)were screened using RNA immunoprecipitation-sequencing(RIP-seq)and IP-mass spectrometry(IP-MS).Results Excessive production of reactive oxygen species(ROS)decreased the expression of the IFN-stimulated gene Dhx58 in hepatocytes and promoted hepatic ferroptosis,while treatment using IFN-αincreased DHX58 expression and prevented ferroptosis during liver I/R injury.Mechanistically,DHX58 with RNA-binding activity constitutively associates with the mRNA of glutathione peroxidase 4(GPX4),a central ferroptosis suppressor,and recruits the m6A reader YT521-B homology domain containing 2(YTHDC2)to promote the translation of Gpx4 mRNA in an m6A-dependent manner,thus enhancing GPX4 protein levels and preventing hepatic ferroptosis.Conclusions This study provides mechanistic evidence that IFN-αstimulates DHX58 to promote the translation of m6A-modified Gpx4 mRNA,suggesting the potential clinical application of IFN-αin the prevention of hepatic ferroptosis during liver I/R injury.
基金supported by the Strategic Priority Research Program of CAS(XDB29010300 to X.Z.)National Natural Science Foundation of China(81873964 to Y.Q.,31800140 to J.M.and 31670161 to X.Z.)+1 种基金National Science and Technology Major Project(2018ZX10101004 to X.Z.)the Science and Technology Development Fund,Macao SAR(0007/2020/A to R.W)。
文摘The ongoing outbreak of Coronavirus Disease 2019(COVID-19)has become a global public health emergency.SARScoronavirus-2(SARS-CoV-2),the causative pathogen of COVID-19,is a positive-sense single-stranded RNA virus belonging to the family Coronaviridae.For RNA viruses,virus-encoded RNA helicases have long been recognized to play pivotal roles during viral life cycles by facilitating the correct folding and replication of viral RNAs.Here,our studies show that SARS-CoV-2-encoded nonstructural protein 13(nsp13)possesses the nucleoside triphosphate hydrolase(NTPase)and RNA helicase activities that can hydrolyze all types of NTPs and unwind RNA helices dependently of the presence of NTP,and further characterize the biochemical characteristics of these two enzymatic activities associated with SARS-CoV-2 nsp13.Moreover,we found that some bismuth salts could effectively inhibit both the NTPase and RNA helicase activities of SARS-CoV-2 nsp13 in a dose-dependent manner.Thus,our findings demonstrate the NTPase and helicase activities of SARS-CoV-2 nsp13,which may play an important role in SARS-CoV-2 replication and serve as a target for antivirals.
基金supported by grants from the National Natural Science Foundation of China (Nos. 31302106, 31260616, and 31602035)the National Key Research and Development Program of China (Nos. 2016YFD0500901 and 2017YFD0500903)
文摘Foot-and-mouth disease virus(FMDV)can infect domestic and wild cloven-hoofed animals.The non-structural protein 3D plays an important role in FMDV replication and pathogenesis.However,the interaction partners of 3D,and the effects of those interactions on FMDV replication,remain incompletely elucidated.In the present study,using the yeast two-hybrid system,we identified a porcine cell protein,DEAD-box RNA helicase 1(DDX1),which interacted with FMDV 3D.The DDX1-3D interaction was further confirmed by co-immunoprecipitation experiments and an indirect immunofluorescence assay(IFA)in porcine kidney 15(PK-15)cells.DDX1 was reported to either inhibit or facilitate viral replication and regulate host innate immune responses.However,the roles of DDX1 during FMDV infection remain unclear.Our results revealed that DDX1 inhibited FMDV replication in an ATPase/helicase activity-dependent manner.In addition,DDX1 stimulated IFN-p activation in FMDV-infected cells.Together,our results expand the body of knowledge regarding the role of DDX1 in FMDV infection.
基金funding support from the National Natural Science Foundation of China(Grant Nos.81672467,81702773,81702389,and 81672368)the Major National R&D Project(Grant Nos.2018ZX10723204,2018ZX10302205,and 2018ZX09J18107)the Natural Science Foundation of Beijing(Grant No.7172207)。
文摘Objective:Hepatocellular carcinoma(HCC),the main type of liver cancer,has a high morbidity and mortality,and a poor prognosis.RNA helicase DDX5,which acts as a transcriptional co-regulator,is overexpressed in most malignant tumors and promotes cancer cell growth.Heat shock protein 90(HSP90)is an important molecular chaperone in the conformational maturation and stabilization of numerous proteins involved in cell growth or survival.Methods:DDX5 m RNA and protein expression in surgically resected HCC tissues from 24 Asian patients were detected by quantitative real-time PCR and Western blot,respectively.The interaction of DDX5-HSP90 was determined by molecular docking,immunoprecipitation,and laser scanning confocal microscopy.The autophagy signal was detected by Western blot.The cell functions and signaling pathways of DDX5 were determined in 2 HCC cell lines.Two different murine HCC xenograft models were used to determine the function of DDX5 and the therapeutic effect of an HSP90 inhibitor.Results:HSP90 interacted directly with DDX5 and inhibited DDX5 protein degradation in the AMPK/ULK1-regulated autophagy pathway.The subsequent accumulation of DDX5 protein induced the malignant phenotype of HCC by activating theβ-catenin signaling pathway.The silencing of DDX5 or treatment with HSP90 inhibitor both blocked in vivo tumor growth in a murine HCC xenograft model.High levels of HSP90 and DDX5 protein were associated with poor prognoses.Conclusions:HSP90 interacted with DDX5 protein and subsequently protected DDX5 protein from AMPK/ULK1-regulated autophagic degradation.DDX5 and HSP90 are therefore potential therapeutic targets for HCC.
基金This study was supported by IRO scholarship Ph.D.Grant.
文摘Recently emerged SARS-CoV-2 caused a major outbreak of coronavirus disease 2019(COVID-19)and instigated a widespread fear,threatening global health safety.To date,no licensed antiviral drugs or vaccines are available against COVID-19 although several clinical trials are under way to test possible therapies.During this urgent situation,computational drug discovery methods provide an alternative to tiresome high-throughput screening,particularly in the hit-to-lead-optimization stage.Identification of small molecules that specifically target viral replication apparatus has indicated the highest potential towards antiviral drug discovery.In this work,we present potential compounds that specifically target SARS-CoV-2 vital proteins,including the main protease,Nsp12 RNA polymerase and Nsp13 helicase.An integrative virtual screening and molecular dynamics simulations approach has facilitated the identification of potential binding modes and favourable molecular interaction profile of corresponding compounds.Moreover,the identification of structurally important binding site residues in conserved motifs located inside the active site highlights relative importance of ligand binding based on residual energy decomposition analysis.Although the current study lacks experimental validation,the structural information obtained from this computational study has paved way for the design of targeted inhibitors to combat COVID-19 outbreak.
基金supported by the Natural Sciences Foundation of China (NSFC, No.30660043)the National Basic Research Program of China (2010CB534912)+1 种基金the Doctoral Program of the Ministry of Education of China (No.200806570003)the Governor Talents Foundation of Guizhou Province (No.200822)
文摘Objective Bloom’s syndrome is an autosomal recessive disorder characterized by genomic instability and a predisposition to many cancers. Mutations of the BLM gene （encoding a BLM helicase） may form a structure of the etiology of this disease. As a global pollutant, mercury poses a major threat to human health. The current study was conducted to elucidate the effects of Hg^2＋ on the structure and activity of BLM642‐1290 recombinant helicase, and to further explore the molecular mechanisms of mercury toxicity to the DNA helicase. Methods The effects of Hg^2＋ on biological activity and structure of BLM642‐1290 recombinant helicase were determined by fluorescence polarized, ultraviolet spectroscopic, and free‐phosphorus assay technologies, respectively. Results The helicase activity, the DNA‐binding activity, and the ATPase activity of BLM642‐1290 recombinant helicase were inhibited by Hg^2＋ treatment. The LMCT （ligand‐to‐metal charge transition） peaks of the helicase were enhanced with the increase of the Hg^2＋ level. The LMCT peaks of the same concentration of helicase gradually increased over time. Conclusions The biological activity of BLM642‐1290 recombinant helicase is inhibited by Hg^2＋ treatment. The conformation of the helicase is significantly altered by Hg^2＋ . There exist two binding sites between Hg^2＋ and the helicase, which are located in the amino acid residues 1063‐1066 and 940‐944 of the helicase, respectively.
基金Supported by Grants from the Ministry of Education of Singapore,Academic Research Fund Tier 1 Grant R-182-000-170-112
文摘The current therapeutic regimen to combat chronic hepatitis C is not optimal due to substantial side effects and the failure of a significant proportion of patients to achieve a sustained virological response. Recently developed direct-acting antivirals targeting hepatitis C virus (HCV) enzymes reportedly increase the virologic response to therapy but may lead to a selection of drug-resistant variants. Besides direct-acting antivirals, another promising class of HCV drugs in development include host targeting agents that are responsible for interfering with the host factors crucial for the viral life cycle. A family of host proteins known as DEAD-box RNA helicases, characterized by nine conserved motifs, is known to play an important role in RNA metabolism. Several members of this family such as DDX3, DDX5 and DDX6 have been shown to play a role in HCV replication and this review will summarize our current knowledge on their interaction with HCV. As chronic hepatitis C is one of the leading causes of hepatocellular carcinoma, the involvement of DEAD-box RNA helicases in the development of HCC will also be highlighted. Continuing research on the interaction of host DEAD-box proteins with HCV and the contribution to viral replication and pathogenesis could be the panacea for the development of novel therapeutics against HCV.
文摘P68 RNA helicase is a prototypical DEAD box RNA helicase. The protein plays a very important role in early organ development and maturation. Consistent with the function of the protein in transcriptional regulation and pre-mRNA splicing, p68 was found to predominately localize in the cell nucleus. However, recent experiments demon- strate a transient cytoplasmic localization of the protein. We report here that p68 shuttles between the nucleus and the cytoplasm. The nucleocytoplasmic shuttling of p68 is mediated by two nuclear localization signal and two nuclear exporting signal sequence elements. Our experiments reveal that p68 shuttles via a classical RanGTPase-dependent pathway.
基金supported by the National Basic Research Program of China (No.2010CB534912)the Doctoral Program of the Ministry of Education (No.200806570003)+1 种基金the Governor of Guizhou Province Talents Fund (No.200822)Guizhou University innovation fundsfor graduate student (No. Nongke 2012027)
文摘Objective To study the effect of fleroxacin （FLRX） on biological properties of Bloom （BLM） helicase catalytic core （BLM 642-2290 helicase） in vitro and the molecular mechanism of interaction between the two molecules. Methods DNA-binding and unwinding activities of BLM 642-1290 helicase were assayed by fluorescence polarization and gel retardation assay under conditions that the helicase was subjected to different concentrations of FLRX. Effect of FLRX on helicase ATPase activity was analyzed by phosphorus-free assay based on a colorimetric estimation of ATP hydrolysis-produced inorganic phosphate. Molecular mechanism of interaction between the two molecules was assayed by ultraviolet and fluorescence spectra. Results The DNA unwinding and ATPase activities of BLM 642-1290 helicase were inhibited whereas the DNA-binding activity was promoted in vitro. A BLM-FLRX complex was formed through one binding site, electrostatic and hydrophobic interaction force. Moreover, the intrinsic fluorescence of the helicase was quenched by FLRX as a result of non-radioactive energy transfer. The biological activity of helicase was affected by FLRX, which may be through an allosteric mechanism and stabilization of enzyme conformation in low helicase activity state, disruption of the coupling of ATP hydrolysis to unwinding, and blocking helicase translocation on DNA strands. Conclusion FLRX may affect the biological activities and conformation of BLM 642-1290 helicase, and DNA helicase may be used as a promising drug target for some diseases.
基金supported by the National Natural Science Foundation of China (82002155 to T.S., and U21A20423 and 31670161 to X.Z.)
文摘RNA-remodeling proteins,including RNA helicases and chaperones,play vital roles in the remodeling of structured RNAs.During viral replication,viruses require RNA-remodeling proteins to facilitate proper folding and/or re-folding the viral RNA elements.Coxsackieviruses B3(CVB3)and Coxsackieviruses B5(CVB5),belonging to the genus Enterovirus in the family Picornaviridae,have been reported to cause various infectious diseases such as hand-foot-and-mouth disease,aseptic meningitis,and viral myocarditis.However,little is known about whether CVB3 and CVB5 encode any RNA remodeling proteins.In this study,we showed that 2C proteins of CVB3 and CVB5 contained the conserved SF3 helicase A,B,and C motifs,and functioned not only as RNA helicase that unwound RNA helix bidirectionally in an NTP-dependent manner,but also as RNA chaperone that remodeled structured RNAs and facilitated RNA strand annealing independently of NTP.In addition,we determined that the NTPase activity and RNA helicase activity of 2C proteins of CVB3 and CVB5 were dependent on the presence of divalent metallic ions.Our findings demonstrate that 2C proteins of CVBs possess RNA-remodeling activity and underline the functional importance of 2C protein in the life cycle of CVBs.
文摘Flaviviruses are positive-sense RNA viruses, and many are important human pathogens. Nonstructural protein 2B and 3 of the flaviviruses(NS2BNS3) form an endoplasmic reticulum(ER) membrane-associated hetero-dimeric complex through the NS2B transmembrane region. The NS2BNS3 complex is multifunctional. The N-terminal region of NS3, and its cofactor NS2B fold into a protease that is responsible for viral polyprotein processing, and the C-terminal domain of NS3 possesses NTPase/RNA helicase activities and is involved in viral RNA replication and virus particle formation. In addition, NS2BNS3 complex has also been shown to modulate viral pathogenesis and the host immune response. Because of the essential functions that the NS2BNS3 complex plays in the flavivirus life cycle, it is an attractive target for antiviral development. This review focuses on the recent biochemical and structural advances of NS2BNS3 and provides a brief update on the current status of drug development targeting this viral protein complex.
基金Project supported by the National Basic Research Program (973) of China (No. 2004CB19604), Distinguished Young Scientist of China (No. 30425038), and the National Natural Science Foundation of China (No. 30330020)
文摘RecQ is a highly conserved helicase necessary for maintaining genome stability in all organisms. Genome comparison showed that a homologue of RecQ in Deinococcus radiodurans designated as DR1289 is a member of RecQ family with unusual domain arrangement: a helicase domain, an RecQ C-terminal domain, and surprisingly three HRDC domain repeats, whose func-tion, however, remains obscure currently. Using an insertion deletion, we discovered that the DRRecQ mutation causes an increase in gamma radiation, hydroxyurea and mitomycine C and UV sensitivity. Using the shuttle plasmid pRADK, we complemented various domains of the D. radiodurans RecQ (DRRecQ) to the mutant in vivo. Results suggested that both the helicase and helicase-and-RNase-D-C-terminal (HRDC) domains are essential for complementing several phenotypes. The complementation and biochemical function of DRRecQ variants with different domains truncated in vitro suggested that both the helicase and three HRDC domains are necessary for RecQ functions in D. radiodurans, while three HRDC domains have a synergistic effect on the whole function. Our finding leads to the hypothesis that the RecF recombination pathway is likely a primary path of double strand break repair in this well-known radioresistant organism.
基金financially supported by grants from the National Natural Science Foundation of China(32072517)the National Key Research and Development Program of China(2018YFD1000105)+2 种基金the Program for Science&Technology Innovation Talents in Universities of Henan Province,China(21HASTIT035)the Program for Innovative Research Team(in Science and Technology)in University of Henan Province,China(21IRTSTHN021)the Science and Technology Planning Project of Luoyang City,China(2101102A)。
文摘Grapevine growing areas are increasingly affected by drought,which has greatly limited global wine production and quality.DEAD-box is one of the largest subfamilies of the RNA helicase family,and its members play key roles in the growth and development of plants and their stress responses.Previous studies have shown the potential of DEAD-box genes in the drought stress responses of Arabidopsis and tomato,rice,and other crop species.However,information about DEAD-box genes in grapevine remains limited.In this report,a total of 40 DEAD-box genes were identified in grapevine and their protein sequence characteristics and gene structures were analyzed.By comparing the expression profiles of VviDEADRHs in response to drought stress in different grapevine varieties,nine candidate genes(VviDEADRH10c,-13,-22,-25a,-25b,-33,-34,-36,and-39)were screened based on expression profiling data.Combined with qRTPCR results,Vvi DEADRH25a was selected for functional verification.Heterologous overexpression of Vvi DEADRH25a in Arabidopsis showed the transgenic plants were more sensitive to drought stress than the control.Both electrolyte permeability and malondialdehyde content were significantly increased in transgenic plants,whereas the chlorophyll content and superoxide dismutase(SOD),peroxidase(POD),catalase(CAT),and ascorbate peroxidase(APX)enzyme activities were significantly decreased.Furthermore,VviDEADRH25a-overexpressing plants showed down-regulated expression levels of several drought stress-related marker genes,namely At COR15a,At RD29A,At ERD15,and At P5CS1,which indicated that they participated in the drought stress response.In summary,this study provides new insights into the structure,evolution,and participation of DEAD-box RNA helicase genes in the response to drought stress in grapevines.
基金The project supported by grants from the Academic Research Fund Tier 1(R-184-000-228-112)the Cancer Science Institute of Singapore,Experimental Therapeutics I Program(grant R-713-001-011-271)
文摘OBJECTIVE To evaluate if RNA helicase DDX20,highly expressed in triple negative breast cancer(TNBC)cells,could serve as a surrogate marker for simvastatin treatment response.METHODS We first assessed correlation between 17 mevalonate pathway-related genes and expression of DDX20 in a cohort of 1325 breast cancer tumors.TNBC cells,MDA-MB-231,were then treated with simvastatin and mevalonate pathway intermediates to assess the alteration in DDX20 expression.In the mouse model,MDA-MB-231 cells were injected to tail veins of mice,groups of 8mice each were injected intraperioneally with vehicle or simvastatin 25mg·kg-1 3times a week for 6weeks.The number of metastatic colonies formed was quantified and immunohistochemical(IHC)staining of DDX20 was carried out in the lung tissues.RESULTS Among the 17 genes evaluated,positive correlation with DDX20 expression was observed in eight of them,with HMGCR having the highest correlation.Our in vitro experiments show exposure of breast cancer cells to simvastatin lead to a Rho-dependent decrease in gene expression of DDX20,leading to decreased tumor proliferation in a mevalonate pathway-dependent manner.Conversely,ectopic overexpression of DDX20 significantly abrogated the anti-metastatic activity of simvastatin.A similar observation is seen in the mouse model,where simvastatin-injected mice show significantly fewer visible lung metastases compared to placebo-fed mice.IHC staining on these lung tissues showed decreased DDX20 expression in simvastatin-injected group,corroborating our observations in vitro.CONCLUSION DDX20 is a potential surrogate marker for simvastatin treatment response in breast cancer and a long term implication of our findings is the possibility of an effective combinatorial therapeutic intervention using statins(to suppress DDX20 gene expression)and a suitable firstline agent″for the kill″of invasive breast cancer.
基金supported by the National Natural Science Foundation of China(Grant Nos.11674383,11474346,and 11274374)the National Basic Research Program of China(Grant No.2013CB837200)the National Key Research and Development Program of China(Grant No.2016YFA0301500)
文摘RecQ5β is an essential DNA helicase in humans, playing important roles in DNA replication, repair, recombination and transcription. The unwinding activity and substrate specificity of RecQ5β is still elusive. Here, we used stopped-flow kinetic method to measure the unwinding and dissociation kinetics of RecQ5β with several kinds of DNA substrates, and found that RecQ5β could well unwind ss/ds DNA, forked DNA and Holiday junction, but was compromised in unwinding blunt DNA and G-quadruplex. Rec5β has the preferred unwinding specificity for certain DNA substrates containing the junction point, which may improve the binding affinity and unwinding activity of RecQ5β. Moreover, from a comparison with the truncated RecQ5β～（1-467）, we discovered that the C-terminal domain might strongly influence the unwinding activity and binding affinity of RecQ5β. These results may shed light on the physiological functions and working mechanisms of RecQ5β helicase.
基金financially supported by the Fundamental Research Funds for the Central Universities(2662018PY041)the Natural Science Foundation of China(31772111)the National Key Research and Development Program of China(2017YFD0201100)。
文摘A significant number of mycoviruses have been identified that are related to plant viruses,but their evolutionary relationships are largely unexplored.A fusarivirus,Rhizoctonia solani fusarivirus 4(RsFV4),was identified in phytopathogenic fungus Rhizoctonia solani(R.solani)strain XY74 co-infected by an alphaendornavirus.RsFV4 had a genome of 10,833 nt(excluding the poly-A tail),and consisted of four non-overlapping open reading frames(ORFs).ORF1 encodes an 825 aa protein containing a conserved helicase domain(Hel1).ORF3 encodes 1550 aa protein with two conserved domains,namely an RNA-dependent RNA polymerase(RdRp)and another helicase(Hel2).The ORF2 and ORF4 likely encode two hypothetical proteins(520 and 542 aa)with unknown functions.The phylogenetic analysis based on Hel2 and RdRp suggest that RsFV4 was positioned within the fusarivirus group,but formed an independent branch with three previously reported fusariviruses of R.solani.Notably,the Hel1 and its relatives were phylogenetically closer to helicases of potyviruses and hypoviruses than fusariviruses,suggesting fusarivirus Hel1 formed an evolutionary link between these three virus groups.This finding provides evidence of the occurrence of a horizontal gene transfer or recombination event between mycoviruses and plant viruses or between mycoviruses.Our findings are likely to enhance the understanding of virus evolution and diversity.
