Single-stranded DNA-binding proteins(SSBs)play essential roles in the replication,recombination and repair processes of organellar DNA molecules.In Arabidopsis thaliana,SSBs are encoded by a small family of two genes(...Single-stranded DNA-binding proteins(SSBs)play essential roles in the replication,recombination and repair processes of organellar DNA molecules.In Arabidopsis thaliana,SSBs are encoded by a small family of two genes(SSB1 and SSB2).However,the functional divergence of these two SSB copies in plants remains largely unknown,and detailed studies regarding their roles in the replication and recombination of organellar genomes are still incomplete.In this study,phylogenetic,gene structure and protein motif analyses all suggested that SSB1 and SSB2 probably diverged during the early evolution of seed plants.Based on accurate long-read sequencing results,ssb1 and ssb2 mutants had decreased copy numbers for both mitochondrial DNA(mtDNA)and plastid DNA(ptDNA),accompanied by a slight increase in structural rearrangements mediated by intermediate-sized repeats in mt genome and small-scale variants in both genomes.Our findings provide an important foundation for further investigating the effects of DNA dosage in the regulation of mutation frequencies in plant organellar genomes.展开更多
A recent study led by Yi-Wei Chang1,published in Science,integrates cryo-electron single-particle analysis(SPA)and cryo-electron tomography(cryo-ET)to elucidate the near-atomic architecture of the influenza virus ribo...A recent study led by Yi-Wei Chang1,published in Science,integrates cryo-electron single-particle analysis(SPA)and cryo-electron tomography(cryo-ET)to elucidate the near-atomic architecture of the influenza virus ribonucleoprotein(RNP)complex.The study reveals that the RNP adopts a right-handed,antiparallel double-helical configuration,in which the viral RNA is translocated via a polymerase-driven strand sliding mechanism.Dynamic tail loop interactions between adjacent nucleoprotein(NP)subunits impart structural flexibility to the RNP,enabling conformational dynamics essential for processive RNA synthesis.These findings define a structural basis for strand sliding,and guided by this insight,the authors identify novel small molecules that disrupt NP–NP interactions by targeting a conserved tail loop interface,laying a foundation for broad-spectrum influenza antivirals.展开更多
High-risk human papillomavirus(HPV)replication requires deregulation of host DNA damage response(DDR)and inflammatory pathways.DNA topoisomerase 2β(Top2β)was previously shown to promote HPV replication.We investigat...High-risk human papillomavirus(HPV)replication requires deregulation of host DNA damage response(DDR)and inflammatory pathways.DNA topoisomerase 2β(Top2β)was previously shown to promote HPV replication.We investigated whether its paralog Top2α protein acts similarly to the virus.Elevated levels of Top2α are consistently observed in cervical intraepithelial lesions and the related carcinomas,as well as in HPV-positive cell lines.Silencing Top2α with shRNA severely suppresses HPV genome maintenance and amplification,but in a DDR-independent manner.Instead,Top2α facilitates secretion of interleukin(IL)-6 and IL-8,which are necessary for HPV replication.Mechanistically,this manipulation is regulated by toll-like receptor 4(TLR4).Top2α binds to the TLR4 promoter to transcriptionally induce TLR4 expression.Blockade of TLR4 signaling by the specific inhibitor TAK-242 significantly reduces the secreted IL-6/IL-8 levels and HPV replication.Overall,our results reveal a novel role of Top2α to shape the inflammatory microenvironment that benefits HPV replication,making it a promising therapeutic target for HPV-associated diseases.展开更多
The DNA replication stress(RS)response is crucial for maintaining cellular homeostasis and promoting physiological longevity.However,the mechanisms by which long-lived species,such as bats,regulate RS to maintain geno...The DNA replication stress(RS)response is crucial for maintaining cellular homeostasis and promoting physiological longevity.However,the mechanisms by which long-lived species,such as bats,regulate RS to maintain genomic stability remain unclear.Also,recent studies have uncovered noncanonical roles of ribosome-associated factors in maintaining genomic stability.In this study,somatic skin fibroblasts from the long-lived big-footed bat(Myotis pilosus)were examined,with results showing that bat cells exhibited enhanced RS tolerance compared to mouse cells.Comparative transcriptome analysis under RS conditions revealed pronounced species-specific transcriptional differences,including robust up-regulation of ribosome biogenesis genes in bat cells and a markedly reduced activation of the P53 signaling pathway.These features emphasize a distinct homeostatic strategy in bat cells.Nuclear fragile X mental retardation-interacting protein 1(Nufip1),a ribosome-associated factor highly expressed in bat fibroblasts,was identified as a potential integrator of ribosomal and P53 signaling via its association with ribosomal protein S27-like(Rps27l).These findings provide direct cellular and molecular evidence for a noncanonical RS response in bats,highlighting a deeper understanding of the biological characteristics and genomic maintenance mechanisms of long-lived species.展开更多
Cloud computing has become an essential technology for the management and processing of large datasets,offering scalability,high availability,and fault tolerance.However,optimizing data replication across multiple dat...Cloud computing has become an essential technology for the management and processing of large datasets,offering scalability,high availability,and fault tolerance.However,optimizing data replication across multiple data centers poses a significant challenge,especially when balancing opposing goals such as latency,storage costs,energy consumption,and network efficiency.This study introduces a novel Dynamic Optimization Algorithm called Dynamic Multi-Objective Gannet Optimization(DMGO),designed to enhance data replication efficiency in cloud environments.Unlike traditional static replication systems,DMGO adapts dynamically to variations in network conditions,system demand,and resource availability.The approach utilizes multi-objective optimization approaches to efficiently balance data access latency,storage efficiency,and operational costs.DMGO consistently evaluates data center performance and adjusts replication algorithms in real time to guarantee optimal system efficiency.Experimental evaluations conducted in a simulated cloud environment demonstrate that DMGO significantly outperforms conventional static algorithms,achieving faster data access,lower storage overhead,reduced energy consumption,and improved scalability.The proposed methodology offers a robust and adaptable solution for modern cloud systems,ensuring efficient resource consumption while maintaining high performance.展开更多
Virus-encoding RNA-dependent RNA polymerase(RdRp)is essential for genome replication and gene transcription of human coronaviruses(HCoVs),including severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).We previo...Virus-encoding RNA-dependent RNA polymerase(RdRp)is essential for genome replication and gene transcription of human coronaviruses(HCoVs),including severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).We previously identified the interaction between the catalytic subunit NSP12 of SARS-CoV-2 RdRp and the host protein CREB-regulated transcription coactivator 3(CRTC3),a member of the CRTC family that regulates cyclic AMP response element-binding protein(CREB)-mediated transcriptional activation.Currently,the implication of CRTC3 in the pathogenesis of HCoVs is poorly understood.Herein,we demonstrated that CRTC3 attenuates RdRp activity and SARS-CoV-2 genome replication,therefore reducing the production of progeny viruses.The interaction of CRTC3 with NSP12 contributes to its inhibitory effect on RdRp activity.Furthermore,we expanded the suppressive effects of two other CRTC family members(CRTC1 and CRTC2)on the RdRp activities of lethal HCoVs,including SARS-CoV-2 and Middle East respiratory syndrome coronavirus(MERS-CoV),along with the CREB antagonization.Overall,our research suggests that CRTCs restrict the replication of HCoVs and are antagonized by CREB,which not only provides new insights into the replication regulation of HCoVs,but also offers important information for the development of anti-HCoV interventions.展开更多
Objective: To evaluate the therapeutic efficacy of replicative adenovirus CNHK500 in the treatment of hepatocellular carcinoma. Methods: Virus proliferation assay, cell viability assay and Western blot were performed ...Objective: To evaluate the therapeutic efficacy of replicative adenovirus CNHK500 in the treatment of hepatocellular carcinoma. Methods: Virus proliferation assay, cell viability assay and Western blot were performed to assess the selective replication and cytolysis of CNHK500 in telomerase positive liver cancer cells Hep3B, HepGII, SMMC7721 and in normal cells. Results: The replicative multiples of CNHK500 in HepGII, Hep3B and SMMC7221 after 96 h of virus proliferation were 52 000, 396 984.9 and 632 911.3 fold respectively, similar to those of wtAd5. However, CNHK500 demonstrated more significant attenuated replicative ability in normal cell lines than wtAd5. CNHK500 replicated only 3.1-100 fold at 96 h, while the wtAd5 still reached 3160-17 357 fold. CNHK500 could cause half of HepGII cells death within 7 days at MOI 2, in Hep3B cell lines the IC50 was as low as MOI 0.01, whereas the IC50 in BJ cell was as high as MOI 1000. CNHK500 E1A protein could only be detected in hepatocellular cancer cells but not in normal cells under normoxia. E1B protein could only be detected under hypoxia condition at a MOI of 1. Conclusion: CNHK500 can efficiently replicate in and kill liver cancer cells as well as wtAd5 do while it is severely attenuated in proliferation and cytolysis among normal cells. It would be a prominsing strategy for liver cancer tratment.展开更多
Dynamic data replication is a technique used in data grid environments that helps to reduce access latency and network bandwidth utilization. Replication also increases data availability thereby enhancing system relia...Dynamic data replication is a technique used in data grid environments that helps to reduce access latency and network bandwidth utilization. Replication also increases data availability thereby enhancing system reliability. In this paper we discuss the issues with single-location strategies in large-scale data integration applications, and examine potential multiple-location schemes. Dynamic multiple-location replication is NP-complete in nature. We therefore transform the multiple-location problem into several classical mathematical problems with different parameter settings, to which efficient approximation algorithms apply experimental results indicate that unlike single-location strategies our multiple-location schemes are efficient with respect to access latency and bandwidth consumption, especially when the requesters of a data set are distributed over a large scale of locations.展开更多
Objective： To evaluate the tumor selectivity and therapeutic efficiency of replication-competent adenovirus CNHK300 on human breast cancer cells. Methods： RT-PCR was used to detect the hTERT mRNA activity in various...Objective： To evaluate the tumor selectivity and therapeutic efficiency of replication-competent adenovirus CNHK300 on human breast cancer cells. Methods： RT-PCR was used to detect the hTERT mRNA activity in various breast cancer and normal fibroblast cell lines. Virus proliferation assay, cell viability assay and Western blot were applied to evaluate the proliferation and cytolysis selectivity of CNHK300. Results： The telomerase activity of MCF-7, BT-549 and SK-BR-3 was positive, while telomerase in MRC-5 and BJ was negative. The progeny virus titers in MCF-7, BT-549 and SK-BR-3 after 48 h of CNHK300 exposure was 40 625, 1 265 and 20 000 fold higher than those of 0 h, even slightly higher than those of wtAd5 （except in SK-BR-3）. ONYX-015 virus proliferation ability was weaker than that of CNHK300 in cancer cells. However, CNHK300 exhibited attenuated replicative ability as compared with wtAd5 in MRC-5 and BJ. The CNHK300 replicatative multiple was 63 and 192 fold at 48 h respectively, while the wtAd5 still multiplied 3 160-4 846 fold. CNHK300 could cause about half of breast cancer cells to die within 7 days at MOI 10 pfu/cell and below, whereas the IC50 in BJ and MRC-5 was as high as MOI 100 pfu/cell. CNHK300 E1A protein could be detected in breast cancer cells and 293 cells but not in normal fibroblast cells. Conclusion： hTERT promoter can successfully modulate the CNHK300 to be selectively replicated in breast cancer cells positive for telomerase, which may be a potential treatment strategy in breast cancer.展开更多
Chronic infection with the hepatitis B virus(HBV) is the leading risk factor for the development of hepatocellular carcinoma(HCC). With nearly 750000 deaths yearly, hepatocellular carcinoma is the second highest cause...Chronic infection with the hepatitis B virus(HBV) is the leading risk factor for the development of hepatocellular carcinoma(HCC). With nearly 750000 deaths yearly, hepatocellular carcinoma is the second highest cause of cancer-related death in the world. Unfortunately, the molecular mechanisms that contribute to the development of HBV-associated HCC remain incompletely understood. Recently, micro RNAs(mi RNAs), a family of small non-coding RNAs that play a role primarily in post-transcriptional gene regulation, have been recognized as important regulators of cellular homeostasis, and altered regulation of mi RNA expression has been suggested to play a significant role in virus-associated diseases and the development of many cancers. With this in mind, many groups have begun to investigate the relationship between mi RNAs and HBV replication and HBV-associated disease. Multiple findings suggest that some mi RNAs, such as mi R-122, and mi R-125 and mi R-199 family members, are playing a role in HBV replication and HBV-associated disease, including the development of HBV-associated HCC. In this review, we discuss the current state of our understanding of the relationship between HBV and mi RNAs, including how HBV affects cellular mi RNAs, how these mi RNAs impact HBV replication, and the relationship between HBV-mediated mi RNA regulation and HCC development. We also address the impact of challenges in studying HBV, such as the lack of an effective model system for infectivity and a reliance on transformed cell lines, on our understanding of the relationship between HBV and mi RNAs, and proposepotential applications of mi RNA-related techniques that could enhance our understanding of the role mi RNAs play in HBV replication and HBV-associated disease, ultimately leading to new therapeutic options and improved patient outcomes.展开更多
AIM:To determine the antiviral mechanism or target of oxymatrine against hepatitis B virus(HBV).METHODS:HepG2.2.15 cells were incubated with culture medium containing 500 μg/mL of oxymatrine for 2 and 5 d.The surface...AIM:To determine the antiviral mechanism or target of oxymatrine against hepatitis B virus(HBV).METHODS:HepG2.2.15 cells were incubated with culture medium containing 500 μg/mL of oxymatrine for 2 and 5 d.The surface antigen of HBV(HBsAg) and e antigen of HBV(HBeAg) in supernatant were determined by ELISA.HBV DNA in supernatant,and intracellular covalently closed circular DNA(cccDNA),relaxed circular DNA(rcDNA) and pregenomic RNA(pgRNA) were quantif ied by specif ic real-time polymerase chain reaction(PCR) or reverse transcription(RT)-PCR.RESULTS:Treatment with oxymatrine for 2 d and 5 d reduced the production of HBV by the cell line,as indicated by the decline of HBsAg(22.67%,t = 5.439,P = 0.0322 and 22.39%,t = 5.376,P = 0.0329,respectively),HBeAg(55.34%,t = 9.859,P = 0.0101 and 43.97%,t = 14.080,P = 0.0050) and HBV DNA(40.75%,t = 4.570,P = 0.0447 and 75.32%,t = 14.460,P = 0.0047) in the supernatant.Intracellular cccDNA was also markedly reduced by 63.98%(t = 6.152,P = 0.0254) and 80.83%(t = 10.270,P = 0.0093),and intracellular rcDNA by 34.35%(t = 4.776,P = 0.0413) and 39.24%(t = 10.050,P = 0.0097).In contrast,intracellular pgRNA increased by 6.90-fold(t = 8.941,P = 0.0123) and 3.18-fold(t = 7.432,P = 0.0176) after 500 μg/mL of oxymatrine treatment for 2 d and 5 d,respectively.CONCLUSION:Oxymatrine may inhibit the replication of HBV by interfering with the process of packaging pgRNA into the nucleocapsid,or inhibiting the activity of the viral DNA polymerase.展开更多
Cellular microRNAs(miRNAs) have been shown to modulate HCV infection via directly acting on the viral genome or indirectly through targeting the virus-associated host factors. Recently we generated a comprehensive map...Cellular microRNAs(miRNAs) have been shown to modulate HCV infection via directly acting on the viral genome or indirectly through targeting the virus-associated host factors. Recently we generated a comprehensive map of HCV–miRNA interactions through genome-wide miRNA functional screens and transcriptomics analyses. Many previously unappreciated cellular miRNAs were identified to be involved in HCV infection, including miR-135a, a human cancerrelated miRNA. In the present study, we investigated the role of miR-135a in regulating HCV life cycle and showed that it preferentially enhances viral genome replication. Bioinformatics-based integrative analyses and subsequent functional assays revealed three antiviral host factors, including receptor interacting serine/threonine kinase 2(RIPK2), myeloid differentiation primary response 88(MYD88), and C-X-C motif chemokine ligand 12(CXCL12), as bona fide targets of miR-135a. These genes have been shown to inhibit HCV infection at the RNA replication stage. Our data demonstrated that repression of key host restriction factors mediated the proviral effect of miR-135a on HCV propagation. In addition,miR-135a hepatic abundance is upregulated by HCV infection in both cultured hepatocytes and human liver, likely mediating a more favorable environment for viral replication and possibly contributing to HCV-induced liver malignancy.These results provide novel insights into HCV–host interactions and unveil molecular pathways linking miRNA biology to HCV pathogenesis.展开更多
The northern pig-tailed macaque （Macaca leonina） has been identified as an independent species of Old World monkey, and we previously found that PBMCs from M. leonina were susceptible to human immunodeficiency virus...The northern pig-tailed macaque （Macaca leonina） has been identified as an independent species of Old World monkey, and we previously found that PBMCs from M. leonina were susceptible to human immunodeficiency virus type 1 （HIV-1）, which may be due to the absence of a TRIM5 protein restricting HIV-1 replication. Here we investigated the infection potentials of six laboratory adapted HIV-1 strains and three primary HIV-1 isolates in PBMCs from M. leonina. The results indicate that these strains are characterized by various but low replication levels, and among which, HIV-INL4-3 shows the highest replication ability. Based on the abundant evidence of species-specific interactions between restriction factors APOBEC3 and HIV/SIV-derived Vif protein, we subsequently examined the replication potentials of v/f-substituted HIV-1 （HSIV） in M. leonina PBMCs. Notably, HSIV-vifmac and stHIV-lsv chimeras, two HIV-1Ni.4-3-derived viruses encoding the viral infectivity factor （Vif） protein from SIVmac239, replicated robustly in cells from M. leonina, which suggests that HSIV could effectively antagonize the antiviral activity of APOBEC3 proteins expressed in cells of M. leonina. Therefore, our data demonstrate that M. leonina has the potential to be developed into a promising animal model for human AIDS.展开更多
基金supported by grants from the National Natural Science Foundation of China(32170238,32400191)Guangdong Basic and Applied Basic Research Foundation(2023A1515111029)+2 种基金the Science,Technology and Innovation Commission of Shenzhen Municipality(RCYX20200714114538196)the Chinese Academy of Agricultural Sciences Elite Youth Program(grant 110243160001007)the Guangdong Pearl River Talent Program(2021QN02N792)。
文摘Single-stranded DNA-binding proteins(SSBs)play essential roles in the replication,recombination and repair processes of organellar DNA molecules.In Arabidopsis thaliana,SSBs are encoded by a small family of two genes(SSB1 and SSB2).However,the functional divergence of these two SSB copies in plants remains largely unknown,and detailed studies regarding their roles in the replication and recombination of organellar genomes are still incomplete.In this study,phylogenetic,gene structure and protein motif analyses all suggested that SSB1 and SSB2 probably diverged during the early evolution of seed plants.Based on accurate long-read sequencing results,ssb1 and ssb2 mutants had decreased copy numbers for both mitochondrial DNA(mtDNA)and plastid DNA(ptDNA),accompanied by a slight increase in structural rearrangements mediated by intermediate-sized repeats in mt genome and small-scale variants in both genomes.Our findings provide an important foundation for further investigating the effects of DNA dosage in the regulation of mutation frequencies in plant organellar genomes.
基金supported by the Key Research and Development Program,Ministry of Science and Technology of the People's Republic of China(No.2023YFC2606500).
文摘A recent study led by Yi-Wei Chang1,published in Science,integrates cryo-electron single-particle analysis(SPA)and cryo-electron tomography(cryo-ET)to elucidate the near-atomic architecture of the influenza virus ribonucleoprotein(RNP)complex.The study reveals that the RNP adopts a right-handed,antiparallel double-helical configuration,in which the viral RNA is translocated via a polymerase-driven strand sliding mechanism.Dynamic tail loop interactions between adjacent nucleoprotein(NP)subunits impart structural flexibility to the RNP,enabling conformational dynamics essential for processive RNA synthesis.These findings define a structural basis for strand sliding,and guided by this insight,the authors identify novel small molecules that disrupt NP–NP interactions by targeting a conserved tail loop interface,laying a foundation for broad-spectrum influenza antivirals.
基金supported by CQMU Program for Youth Innovation in Future Medicine(172020320220090 W0072)to S.H.Chongqing Yuzhong District Basic Research and Frontier Exploration Project(20210128)to S.H.+1 种基金Natural Science Program of Chongqing Science and Technology Commission(2024NSCQ-KJFZZDX)to S.H.National Natural Science foundation of China(NSFC)Young Scientists Fund(82300970).
文摘High-risk human papillomavirus(HPV)replication requires deregulation of host DNA damage response(DDR)and inflammatory pathways.DNA topoisomerase 2β(Top2β)was previously shown to promote HPV replication.We investigated whether its paralog Top2α protein acts similarly to the virus.Elevated levels of Top2α are consistently observed in cervical intraepithelial lesions and the related carcinomas,as well as in HPV-positive cell lines.Silencing Top2α with shRNA severely suppresses HPV genome maintenance and amplification,but in a DDR-independent manner.Instead,Top2α facilitates secretion of interleukin(IL)-6 and IL-8,which are necessary for HPV replication.Mechanistically,this manipulation is regulated by toll-like receptor 4(TLR4).Top2α binds to the TLR4 promoter to transcriptionally induce TLR4 expression.Blockade of TLR4 signaling by the specific inhibitor TAK-242 significantly reduces the secreted IL-6/IL-8 levels and HPV replication.Overall,our results reveal a novel role of Top2α to shape the inflammatory microenvironment that benefits HPV replication,making it a promising therapeutic target for HPV-associated diseases.
基金supported by the Applied Basic Research Programs of Science and Technology Commission Foundation of Yunnan Province(202401AT070186 to K.Q.L.,202201AS070044 to B.Z.)Yunnan Province(202305AH340006 to B.Z.)Kunming Science and Technology Bureau(2022SCP007 to B.Z.)。
文摘The DNA replication stress(RS)response is crucial for maintaining cellular homeostasis and promoting physiological longevity.However,the mechanisms by which long-lived species,such as bats,regulate RS to maintain genomic stability remain unclear.Also,recent studies have uncovered noncanonical roles of ribosome-associated factors in maintaining genomic stability.In this study,somatic skin fibroblasts from the long-lived big-footed bat(Myotis pilosus)were examined,with results showing that bat cells exhibited enhanced RS tolerance compared to mouse cells.Comparative transcriptome analysis under RS conditions revealed pronounced species-specific transcriptional differences,including robust up-regulation of ribosome biogenesis genes in bat cells and a markedly reduced activation of the P53 signaling pathway.These features emphasize a distinct homeostatic strategy in bat cells.Nuclear fragile X mental retardation-interacting protein 1(Nufip1),a ribosome-associated factor highly expressed in bat fibroblasts,was identified as a potential integrator of ribosomal and P53 signaling via its association with ribosomal protein S27-like(Rps27l).These findings provide direct cellular and molecular evidence for a noncanonical RS response in bats,highlighting a deeper understanding of the biological characteristics and genomic maintenance mechanisms of long-lived species.
文摘Cloud computing has become an essential technology for the management and processing of large datasets,offering scalability,high availability,and fault tolerance.However,optimizing data replication across multiple data centers poses a significant challenge,especially when balancing opposing goals such as latency,storage costs,energy consumption,and network efficiency.This study introduces a novel Dynamic Optimization Algorithm called Dynamic Multi-Objective Gannet Optimization(DMGO),designed to enhance data replication efficiency in cloud environments.Unlike traditional static replication systems,DMGO adapts dynamically to variations in network conditions,system demand,and resource availability.The approach utilizes multi-objective optimization approaches to efficiently balance data access latency,storage efficiency,and operational costs.DMGO consistently evaluates data center performance and adjusts replication algorithms in real time to guarantee optimal system efficiency.Experimental evaluations conducted in a simulated cloud environment demonstrate that DMGO significantly outperforms conventional static algorithms,achieving faster data access,lower storage overhead,reduced energy consumption,and improved scalability.The proposed methodology offers a robust and adaptable solution for modern cloud systems,ensuring efficient resource consumption while maintaining high performance.
基金supported by grants from the National Natural Science Foundation of China(32071236)the National Science Fund for Distinguished Young Scholars(32225001)+6 种基金the 1.3.5 Project for Disciplines Excellence of West China Hospital,Sichuan University(ZYGD23018)Key Science and Technology Research Projects in Key Areas of the Corps(2023AB053)the National Key Research and Development Program of China(2022YFC2303700)the Joint Project of Pengzhou People's Hospital with Southwest Medical University(2024PZXNYD02)Project funded by China Postdoctoral Science Foundation(2020M683304)Sichuan Science and Technology Support Project(2021YJ0502)Post-Doctor Research Project,West China Hospital,Sichuan University(2020HXBH082).
文摘Virus-encoding RNA-dependent RNA polymerase(RdRp)is essential for genome replication and gene transcription of human coronaviruses(HCoVs),including severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).We previously identified the interaction between the catalytic subunit NSP12 of SARS-CoV-2 RdRp and the host protein CREB-regulated transcription coactivator 3(CRTC3),a member of the CRTC family that regulates cyclic AMP response element-binding protein(CREB)-mediated transcriptional activation.Currently,the implication of CRTC3 in the pathogenesis of HCoVs is poorly understood.Herein,we demonstrated that CRTC3 attenuates RdRp activity and SARS-CoV-2 genome replication,therefore reducing the production of progeny viruses.The interaction of CRTC3 with NSP12 contributes to its inhibitory effect on RdRp activity.Furthermore,we expanded the suppressive effects of two other CRTC family members(CRTC1 and CRTC2)on the RdRp activities of lethal HCoVs,including SARS-CoV-2 and Middle East respiratory syndrome coronavirus(MERS-CoV),along with the CREB antagonization.Overall,our research suggests that CRTCs restrict the replication of HCoVs and are antagonized by CREB,which not only provides new insights into the replication regulation of HCoVs,but also offers important information for the development of anti-HCoV interventions.
基金This work is supported by International Cooperation Important Project of National Natural Science Foundation of China(No.30120160824)the State 863 High Technology R&D Project of China(No.2001AA217031).
文摘Objective: To evaluate the therapeutic efficacy of replicative adenovirus CNHK500 in the treatment of hepatocellular carcinoma. Methods: Virus proliferation assay, cell viability assay and Western blot were performed to assess the selective replication and cytolysis of CNHK500 in telomerase positive liver cancer cells Hep3B, HepGII, SMMC7721 and in normal cells. Results: The replicative multiples of CNHK500 in HepGII, Hep3B and SMMC7221 after 96 h of virus proliferation were 52 000, 396 984.9 and 632 911.3 fold respectively, similar to those of wtAd5. However, CNHK500 demonstrated more significant attenuated replicative ability in normal cell lines than wtAd5. CNHK500 replicated only 3.1-100 fold at 96 h, while the wtAd5 still reached 3160-17 357 fold. CNHK500 could cause half of HepGII cells death within 7 days at MOI 2, in Hep3B cell lines the IC50 was as low as MOI 0.01, whereas the IC50 in BJ cell was as high as MOI 1000. CNHK500 E1A protein could only be detected in hepatocellular cancer cells but not in normal cells under normoxia. E1B protein could only be detected under hypoxia condition at a MOI of 1. Conclusion: CNHK500 can efficiently replicate in and kill liver cancer cells as well as wtAd5 do while it is severely attenuated in proliferation and cytolysis among normal cells. It would be a prominsing strategy for liver cancer tratment.
基金the National Natural Science Foundation of China (70671011)the National High-Technology Research and Development Program of China (863 Program) (2007AA04Z1B1)the Social Science Youth Foundation of Chongqing University ( CDSK2007-37)
文摘Dynamic data replication is a technique used in data grid environments that helps to reduce access latency and network bandwidth utilization. Replication also increases data availability thereby enhancing system reliability. In this paper we discuss the issues with single-location strategies in large-scale data integration applications, and examine potential multiple-location schemes. Dynamic multiple-location replication is NP-complete in nature. We therefore transform the multiple-location problem into several classical mathematical problems with different parameter settings, to which efficient approximation algorithms apply experimental results indicate that unlike single-location strategies our multiple-location schemes are efficient with respect to access latency and bandwidth consumption, especially when the requesters of a data set are distributed over a large scale of locations.
基金This work was supported by International Cooperation Important Project of National Natural Sciences Foundation of China(No. 30120160824) and the State 863 High Technology R&D Project of China (No. 2001AA217031)
文摘Objective： To evaluate the tumor selectivity and therapeutic efficiency of replication-competent adenovirus CNHK300 on human breast cancer cells. Methods： RT-PCR was used to detect the hTERT mRNA activity in various breast cancer and normal fibroblast cell lines. Virus proliferation assay, cell viability assay and Western blot were applied to evaluate the proliferation and cytolysis selectivity of CNHK300. Results： The telomerase activity of MCF-7, BT-549 and SK-BR-3 was positive, while telomerase in MRC-5 and BJ was negative. The progeny virus titers in MCF-7, BT-549 and SK-BR-3 after 48 h of CNHK300 exposure was 40 625, 1 265 and 20 000 fold higher than those of 0 h, even slightly higher than those of wtAd5 （except in SK-BR-3）. ONYX-015 virus proliferation ability was weaker than that of CNHK300 in cancer cells. However, CNHK300 exhibited attenuated replicative ability as compared with wtAd5 in MRC-5 and BJ. The CNHK300 replicatative multiple was 63 and 192 fold at 48 h respectively, while the wtAd5 still multiplied 3 160-4 846 fold. CNHK300 could cause about half of breast cancer cells to die within 7 days at MOI 10 pfu/cell and below, whereas the IC50 in BJ and MRC-5 was as high as MOI 100 pfu/cell. CNHK300 E1A protein could be detected in breast cancer cells and 293 cells but not in normal fibroblast cells. Conclusion： hTERT promoter can successfully modulate the CNHK300 to be selectively replicated in breast cancer cells positive for telomerase, which may be a potential treatment strategy in breast cancer.
基金Supported by Pennsylvania state CURE grant,No.4100057658,[to Steel LF and Bouchard MJ(partially)]a Ruth L Kirschstein(F31)Predoctoral Fellowship,No.5F31CA171712-03,[to Lamontagne J(partially)]
文摘Chronic infection with the hepatitis B virus(HBV) is the leading risk factor for the development of hepatocellular carcinoma(HCC). With nearly 750000 deaths yearly, hepatocellular carcinoma is the second highest cause of cancer-related death in the world. Unfortunately, the molecular mechanisms that contribute to the development of HBV-associated HCC remain incompletely understood. Recently, micro RNAs(mi RNAs), a family of small non-coding RNAs that play a role primarily in post-transcriptional gene regulation, have been recognized as important regulators of cellular homeostasis, and altered regulation of mi RNA expression has been suggested to play a significant role in virus-associated diseases and the development of many cancers. With this in mind, many groups have begun to investigate the relationship between mi RNAs and HBV replication and HBV-associated disease. Multiple findings suggest that some mi RNAs, such as mi R-122, and mi R-125 and mi R-199 family members, are playing a role in HBV replication and HBV-associated disease, including the development of HBV-associated HCC. In this review, we discuss the current state of our understanding of the relationship between HBV and mi RNAs, including how HBV affects cellular mi RNAs, how these mi RNAs impact HBV replication, and the relationship between HBV-mediated mi RNA regulation and HCC development. We also address the impact of challenges in studying HBV, such as the lack of an effective model system for infectivity and a reliance on transformed cell lines, on our understanding of the relationship between HBV and mi RNAs, and proposepotential applications of mi RNA-related techniques that could enhance our understanding of the role mi RNAs play in HBV replication and HBV-associated disease, ultimately leading to new therapeutic options and improved patient outcomes.
基金Supported by The National Natural Scientifi c Foundation of China,No. 30070958The National Key Technologies Research and Development Program of China during the 11th Five-year Plan Period,No. 2008zx1002-006
文摘AIM:To determine the antiviral mechanism or target of oxymatrine against hepatitis B virus(HBV).METHODS:HepG2.2.15 cells were incubated with culture medium containing 500 μg/mL of oxymatrine for 2 and 5 d.The surface antigen of HBV(HBsAg) and e antigen of HBV(HBeAg) in supernatant were determined by ELISA.HBV DNA in supernatant,and intracellular covalently closed circular DNA(cccDNA),relaxed circular DNA(rcDNA) and pregenomic RNA(pgRNA) were quantif ied by specif ic real-time polymerase chain reaction(PCR) or reverse transcription(RT)-PCR.RESULTS:Treatment with oxymatrine for 2 d and 5 d reduced the production of HBV by the cell line,as indicated by the decline of HBsAg(22.67%,t = 5.439,P = 0.0322 and 22.39%,t = 5.376,P = 0.0329,respectively),HBeAg(55.34%,t = 9.859,P = 0.0101 and 43.97%,t = 14.080,P = 0.0050) and HBV DNA(40.75%,t = 4.570,P = 0.0447 and 75.32%,t = 14.460,P = 0.0047) in the supernatant.Intracellular cccDNA was also markedly reduced by 63.98%(t = 6.152,P = 0.0254) and 80.83%(t = 10.270,P = 0.0093),and intracellular rcDNA by 34.35%(t = 4.776,P = 0.0413) and 39.24%(t = 10.050,P = 0.0097).In contrast,intracellular pgRNA increased by 6.90-fold(t = 8.941,P = 0.0123) and 3.18-fold(t = 7.432,P = 0.0176) after 500 μg/mL of oxymatrine treatment for 2 d and 5 d,respectively.CONCLUSION:Oxymatrine may inhibit the replication of HBV by interfering with the process of packaging pgRNA into the nucleocapsid,or inhibiting the activity of the viral DNA polymerase.
基金supported by the Intramural Research Program of the National Institute of Diabetes and Digestive and Kidney Diseases, US National Institutes of Health
文摘Cellular microRNAs(miRNAs) have been shown to modulate HCV infection via directly acting on the viral genome or indirectly through targeting the virus-associated host factors. Recently we generated a comprehensive map of HCV–miRNA interactions through genome-wide miRNA functional screens and transcriptomics analyses. Many previously unappreciated cellular miRNAs were identified to be involved in HCV infection, including miR-135a, a human cancerrelated miRNA. In the present study, we investigated the role of miR-135a in regulating HCV life cycle and showed that it preferentially enhances viral genome replication. Bioinformatics-based integrative analyses and subsequent functional assays revealed three antiviral host factors, including receptor interacting serine/threonine kinase 2(RIPK2), myeloid differentiation primary response 88(MYD88), and C-X-C motif chemokine ligand 12(CXCL12), as bona fide targets of miR-135a. These genes have been shown to inhibit HCV infection at the RNA replication stage. Our data demonstrated that repression of key host restriction factors mediated the proviral effect of miR-135a on HCV propagation. In addition,miR-135a hepatic abundance is upregulated by HCV infection in both cultured hepatocytes and human liver, likely mediating a more favorable environment for viral replication and possibly contributing to HCV-induced liver malignancy.These results provide novel insights into HCV–host interactions and unveil molecular pathways linking miRNA biology to HCV pathogenesis.
基金Foundation items： This work was supported by the National Basic Research Program （2012CBA01305） the National Natural Science Foundation of China （81172876, U0832601, 81273251 and U 1202228） the Knowledge Innovation Program of CAS （KSCX2-EW-R-13, Y206A- 71181）, and the Key Scientific and Technological Program of China （2012ZX10001-007, 2013ZX10001-002）. Acknowledgements： We thank Prof. Guang-Xia GAO （Institute of Biophysics, Chinese Academy of Sciences） for kindly providing HSIV proviral plasmids.We also thank Long-Bao LV, Gui LI and Dong- Ti HUANG of Kunming Primate Research Center for their assistance in obtaining blood samples from northem pig-tailed macaques （M. leonina） and Chinese rhesus macaques.
文摘The northern pig-tailed macaque （Macaca leonina） has been identified as an independent species of Old World monkey, and we previously found that PBMCs from M. leonina were susceptible to human immunodeficiency virus type 1 （HIV-1）, which may be due to the absence of a TRIM5 protein restricting HIV-1 replication. Here we investigated the infection potentials of six laboratory adapted HIV-1 strains and three primary HIV-1 isolates in PBMCs from M. leonina. The results indicate that these strains are characterized by various but low replication levels, and among which, HIV-INL4-3 shows the highest replication ability. Based on the abundant evidence of species-specific interactions between restriction factors APOBEC3 and HIV/SIV-derived Vif protein, we subsequently examined the replication potentials of v/f-substituted HIV-1 （HSIV） in M. leonina PBMCs. Notably, HSIV-vifmac and stHIV-lsv chimeras, two HIV-1Ni.4-3-derived viruses encoding the viral infectivity factor （Vif） protein from SIVmac239, replicated robustly in cells from M. leonina, which suggests that HSIV could effectively antagonize the antiviral activity of APOBEC3 proteins expressed in cells of M. leonina. Therefore, our data demonstrate that M. leonina has the potential to be developed into a promising animal model for human AIDS.
