Hearing relies on the structural and functional integrity of cochlear hair cells,particularly their apical F-actin-filled stereocilia.Phospholipid scramblases are important for maintaining membrane asymmetry,but their...Hearing relies on the structural and functional integrity of cochlear hair cells,particularly their apical F-actin-filled stereocilia.Phospholipid scramblases are important for maintaining membrane asymmetry,but their roles in the stereocilia and auditory functions are not fully understood.Here,we identify Plscr5 as a downstream target of the transcription factor POU4F3 essential for hair cell function,whose mutation causes human DFNA15 deafness.Plscr5 knockout mice exhibit progressive hearing loss due to stereocilia degeneration and hair cell loss.Functional analyses reveal that PLSCR5 contributes to phosphatidylserine externalization in hair cell apical membranes,particularly in inner hair cells,and is important for outer hair cell and stereocilia maintenance.Our findings highlight PLSCR5 as an important downstream effector of POU4F3 and regulator of phosphatidylserine externalization and membrane dynamics required for auditory functions.展开更多
The persistence of covalently closed circular DNA(cccDNA)in hepatitis B virus(HBV)-infected hepatocytes remains a major obstacle to effective antiviral treatment.Understanding the molecular mechanisms regulating HBV c...The persistence of covalently closed circular DNA(cccDNA)in hepatitis B virus(HBV)-infected hepatocytes remains a major obstacle to effective antiviral treatment.Understanding the molecular mechanisms regulating HBV cccDNA transcription is essential for developing novel therapeutic strategies.In this study,we investigated the role of RNA binding motif protein 25(RBM25)in HBV replication,focusing on its interaction with cccDNA and its regulation of host transcription factors.The results demonstrated that RBM25 knockdown markedly inhibited HBV replication,reducing levels of HBV DNA,hepatitis B e antigen(HBeAg),hepatitis B surface antigen(HBsAg),HBV RNA,and L-HBs in HBV-replicating and infected cell models.Consistent results were observed in a mouse model hydrodynamically injected with 1.2HBV plasmid.Conversely,RBM25 overexpression significantly enhanced HBV replication.Mechanistically,RBM25 promoted HBV promoter activities by binding to cccDNA through its RE/RD and PWI domains.This effect was mediated by increased Yin Yang 1(YY1)expression,which enhanced acetylation of cccDNA-bound histones,promoting HBV transcription.Furthermore,RBM25 expression was upregulated and translocated to the nucleus following core protein expression and accumulation,while overexpression of RBM25 promoted core protein degradation.In conclusion,this study demonstrates that RBM25 is a novel host factor that enhances HBV replication by upregulating YY1-dependent transcriptional activation of cccDNA.It also reveales a reciprocal regulatory mechanism between the HBV core protein and RBM25,which helps sustain HBV replication.展开更多
Accurate timing of myelination is crucial for the proper functioning of the central nervous system. Here, we identified a de novo heterozygous mutation in TMEM63A (c.1894G>A;p. Ala632Thr) in a 7-year-old boy exhibi...Accurate timing of myelination is crucial for the proper functioning of the central nervous system. Here, we identified a de novo heterozygous mutation in TMEM63A (c.1894G>A;p. Ala632Thr) in a 7-year-old boy exhibiting hypomyelination. A Ca2+ influx assay suggested that this is a loss-of-function mutation. To explore how TMEM63A deficiency causes hypomyelination, we generated Tmem63a knockout mice. Genetic deletion of TMEM63A resulted in hypomyelination at postnatal day 14 (P14) arising from impaired differentiation of oligodendrocyte precursor cells (OPCs). Notably, the myelin dysplasia was transient, returning to normal levels by P28. Primary cultures of Tmem63a^(−/−) OPCs presented delayed differentiation. Lentivirus-based expression of TMEM63A but not TMEM63A_A632T rescued the differentiation of Tmem63a^(−/−) OPCs in vitro and myelination in Tmem63a^(−/−) mice. These data thus support the conclusion that the mutation in TMEM63A is the pathogenesis of the hypomyelination in the patient. Our study further demonstrated that TMEM63A-mediated Ca^(2+) influx plays critical roles in the early development of myelin and oligodendrocyte differentiation.展开更多
Objective:Herbal medicine is an important therapeutic option for benign prostatic hyperplasia(BPH),a common disease in older men that can seriously affect their quality of life.Currently,it is crucial to develop agent...Objective:Herbal medicine is an important therapeutic option for benign prostatic hyperplasia(BPH),a common disease in older men that can seriously affect their quality of life.Currently,it is crucial to develop agents with strong efficacy and few side effects.Herein we investigated the effects of the extract of Rauwolfia vomitoria,a shrub grown in West Africa,on BPH.Methods:Rats with testosterone-induced BPH were treated with R.vomitoria.Prostates were histologically analyzed by Hematoxylin and eosin staining.Proliferation index and the expression levels of androgen receptor and its associated proteins were quantified through immunohistochemistry and immunoblotting.Androgen receptor target genes were examined by quantitative real-time polymerase chain reaction.The sperm count and body weight of rats were also measured.Results:The oral administration of R.vomitoria extract significantly reduced the prostate weight and prostate weight index in BPH rats,supported by the decreased thickness of the prostate epithelial layer and increased lumen size.Similar effects were observed in the BPH rats treated with the reference drug,finasteride.R.vomitoria extract significantly reduced the testosterone-induced proliferation markers,including proliferating cell nuclear antigen and cyclin D1,in the prostate glands of BPH rats;it also reduced levels of androgen receptor,its associated protein steroid 5 a-reductase 1 and its downstream target genes(FK506-binding protein 5 and matrix metalloproteinase 2).Notably,compared with the finasteride group,R.vomitoria extract did not significantly reduce sperm count.Conclusion:R.vomitoria suppresses testosterone-induced BPH development.Due to its milder side effects,R.vomitoria could be a promising therapeutic agent for BPH.展开更多
Sound transmission occurs in the cochlea,a complex and ingenious subdivision in the inner ear.The structure of the cochlea develops structurally and functionally by the time before two postnatal weeks(the time of hear...Sound transmission occurs in the cochlea,a complex and ingenious subdivision in the inner ear.The structure of the cochlea develops structurally and functionally by the time before two postnatal weeks(the time of hearing onset)in mice(Geal-Dor et al.,1993).Greater epithelial ridge(GER,also known as Kolliker's organ)is a transient cochlear structure containing a group of columnar epithelial supporting cells surrounding the inner hair cells(IHCs).展开更多
The highly conserved target of rapamycin(TOR)pathway plays an important role in aging across species.Previous studies have established that inhibition of the TOR complex 1(TORC1)significantly extends lifespan in Caeno...The highly conserved target of rapamycin(TOR)pathway plays an important role in aging across species.Previous studies have established that inhibition of the TOR complex 1(TORC1)significantly extends lifespan in Caenorhabditis elegans.However,it has not been clear whether TORC1 perturbation affects aging in a spatiotemporal manner.Here,we apply the auxin-inducible degradation tool to knock down endogenous DAF-15,the C.elegans ortholog of regulatory associated protein of TOR(Raptor),to characterize its roles in aging.Global or tissue-specific inhibition of DAF-15 during development results in various growth defects,whereas neuron-specific knockdown of DAF-15 during adulthood significantly extends lifespan and healthspan.The neuronal DAF-15 deficiency-induced longevity requires the intestinal activities of DAF-16/FOXO and PHA-4/FOXA transcription factors,as well as the AAK-2/AMP-activated protein kinaseαcatalytic subunit.Transcriptome profiling reveals that the neuronal DAF-15 knockdown promotes the expression of genes involved in protection.These findings define the tissue-specific roles of TORC1 in healthy aging and highlight the importance of neuronal modulation of aging.展开更多
Accumulation of mutant proteins in cells can induce proteinopathies and cause functional damage to organs.Recently,the Cingulin(CGN)protein has been shown to maintain the morphology of cuticular plates of inner ear ha...Accumulation of mutant proteins in cells can induce proteinopathies and cause functional damage to organs.Recently,the Cingulin(CGN)protein has been shown to maintain the morphology of cuticular plates of inner ear hair cells and a frameshift mutation in CGN causes autosomal dominant non-syndromic hearing loss.Here,we find that the mutant CGN proteins form insoluble aggregates which accumulate intracellularly and lead to cell death.Expression of the mutant CGN in the inner ear results in severe hair cell death and hearing loss in mice,resembling the auditory phenotype in human patients.Interestingly,a human-specific residue(V1112)in the neopeptide generated by the frameshift mutation is critical for the aggregation and cytotoxicity of the mutant human CGN.Moreover,the expression of heat shock factor 1(HSF1)decreases the accumulation of insoluble mutant CGN aggregates and rescues cell death.In summary,these findings identify mutant-specific toxic polypeptides as a disease-causing mechanism of the deafness mutation in CGN,which can be targeted by the expression of the cell chaperone response regulator HSF1.展开更多
Netrin-G2 is a membrane-anchored protein known to play critical roles in neuronal circuit development and synaptic organization.In this study,we identify compound heterozygous mutations of c.547delC p.(Arg183Alafs*186...Netrin-G2 is a membrane-anchored protein known to play critical roles in neuronal circuit development and synaptic organization.In this study,we identify compound heterozygous mutations of c.547delC p.(Arg183Alafs*186)and c.605G>A,p.(Trp202X)in NTNG2 causing a syndrome exhibiting developmenta delay,intellectual disability,hypotonia,and facial dysmorphism.To elucidate the underlying cellular and molecular mechanisms,CRISPR-Cas9 technology is employed to generate a knock-in mouse mode expressing the R183Afs and W202X mutations.We report that the Ntng2^(R183Afs/W202X)mice exhibit hypo tonia and impaired learning and memory.We find that the levels of CaMKII and p-GluA1^(Ser831)are decreased,and excitatory postsynaptic transmission and long-term potentiation are impaired.To increase the activity of CaMKII,the mutant mice receive intraperitoneal injections of DCP-LA,a CaMKII agonist,and show improved cognitive function.Together,our findings reveal molecular mechanisms of how NTNG2deficiency leads to impairments of cognitive ability and synaptic plasticity.展开更多
In mammals,the neonatal heart can regenerate upon injury within a short time after birth,while adults lose this ability.Metabolic reprogramming has been demonstrated to be critical for cardiomyocyte proliferation in t...In mammals,the neonatal heart can regenerate upon injury within a short time after birth,while adults lose this ability.Metabolic reprogramming has been demonstrated to be critical for cardiomyocyte proliferation in the neonatal heart.Here,we reveal that cardiac metabolic reprogramming could be regulated by altering global protein lactylation.By performing 4D label-free proteomics and lysine lactylation(Kla)omics analyses in mouse hearts at postnatal days 1,5,and 7,2297 Kla sites from 980 proteins are identified,among which 1262 Kla sites from 409 proteins are quantified.Functional clustering analysis reveals that the proteins with altered Kla sites are mainly involved in metabolic processes.The expression and Kla levels of proteins in glycolysis show a positive correlation while a negative correlation in fatty acid oxidation.Furthermore,we verify the Kla levels of several differentially modified proteins,including ACAT1,ACADL,ACADVL,PFKM,PKM,and NPM1.Overall,our study reports a comprehensive Kla map in the neonatal mouse heart,which will help to understand the regulatory network of metabolic reprogramming and cardiac regeneration.展开更多
Meiosis is a highly complex process significantly influenced by transcriptional regulation.However,studies on the mechanisms that govern transcriptomic changes during meiosis,especially in prophase I,are limited.Here,...Meiosis is a highly complex process significantly influenced by transcriptional regulation.However,studies on the mechanisms that govern transcriptomic changes during meiosis,especially in prophase I,are limited.Here,we performed single-cell ATAC-seq of human testis tissues and observed reprogramming during the transition from zygotene to pachytene spermatocytes.This event,conserved in mice,involved the deactivation of genes associated with meiosis after reprogramming and the activation of those related to spermatogenesis before their functional onset.Furthermore,we identified 282 transcriptional regulators(TRs)that underwent activation or deactivation subsequent to this process.Evidence suggested that physical contact signals from Sertoli cells may regulate these TRs in spermatocytes,while secreted ENHO signals may alter metabolic patterns in these cells.Our results further indicated that defective transcriptional reprogramming may be associated with non-obstructive azoospermia(NOA).This study revealed the importance of both physical contact and secreted signals between Sertoli cells and germ cells in meiotic progression.展开更多
Looking back a decade ago when I decided to use ＂model animal＂ to name our newly established institute, my outrageous boldness can only be described by the old Chinese slang, ＂newborn calf could never sense the dan...Looking back a decade ago when I decided to use ＂model animal＂ to name our newly established institute, my outrageous boldness can only be described by the old Chinese slang, ＂newborn calf could never sense the danger of tiger＂. Happily, my courageous belief, along with the hard work of my colleagues at Model Animal Research Center of Nanjing University, paid off eventually. We have witnessed the great progress in this research field in China in the past 10 years. This issue of Science China Life Sciences samplings some of these accomplishments.展开更多
Several factors have been implicated in obesity-related hypertension, but the genesis of the hypertension is largely unknown. In this study, we found a significantly upregulated expression of CPI-17(C-kinasepotentiate...Several factors have been implicated in obesity-related hypertension, but the genesis of the hypertension is largely unknown. In this study, we found a significantly upregulated expression of CPI-17(C-kinasepotentiated protein phosphatase 1 inhibitor of 17 kDa) and protein kinase C(PKC) isoforms in the vascular smooth muscles of high-fat diet(HFD)-fed obese mice. The obese wild-type mice showed a significant elevation of blood pressure and enhanced calcium-sensitized contraction of vascular smooth muscles. However, the obese CPI-17-deficient mice showed a normotensive blood pressure, and the calcium-sensitized contraction was consistently reduced. In addition, the mutant muscle displayed an abolished responsive force to a PKC activator and a 30%-50% reduction in both the initial peak force and sustained force in response to various G protein-coupled receptor(GPCR) agonists. Our observations showed that CPI-17-mediated calcium sensitization is mediated through a GPCR/PKC/CPI-17/MLCP/RLC signaling pathway. We therefore propose that the upregulation of CPI-17-mediated calcium-sensitized vasocontraction by obesity contributes to the development of obesity-related hypertension.展开更多
Recovery from injury to the peripheral nervous system is different from that of the central nervous system in that it can lead to gene reprogramming that can induce the expression of a series of regeneration-associate...Recovery from injury to the peripheral nervous system is different from that of the central nervous system in that it can lead to gene reprogramming that can induce the expression of a series of regeneration-associated genes.This eventually leads to axonal regeneration of injured neurons.Although some regeneration-related genes have been identified,the regulatory network underlying axon regeneration remains largely unknown.To explore the regulator of axon regeneration,we performed RNA sequencing of lumbar L4 and L5 dorsal root ganglion(DRG)neurons at different time points(0,3,6,12 hours,1,3 and 7 days)after rat sciatic nerve crush.The isolation of neurons was carried out by laser capture microscopy combined with NeuN immunofluorescence staining.We found 1228 differentially expressed genes in the injured sciatic nerve tissue.The hub genes within these differentially expressed genes include Atf3,Jun,Myc,Ngf,Fgf2,Ezh2,Gfap and Il6.We verified that the expression of the enhancer of zeste homologue 2 gene(Ezh2)was up-regulated in DRG neurons after injury,and this up-regulation differed between large-and small-sized dorsal root ganglion neurons.To investigate whether the up-regulation of Ezh2 impacts axonal regeneration,we silenced Ezh2 with siRNA in cultured DRG neurons and found that the growth of the newborn axons was repressed.In our investigation into the regulatory network of Ezh2 by interpretive phenomenal analysis,we found some regulators of Ezh2(including Erk,Il6 and Hif1a)and targets(including Atf3,Cdkn1a and Smad1).Our findings suggest that Ezh2,as a nerve regeneration-related gene,participates in the repair of the injured DRG neurons,and knocking down the Ezh2 in vitro inhibits the axonal growth of DRG neurons.All the experimental procedures approved by the Administration Committee of Experimental Animals of Jiangsu Province of China(approval No.S20191201-201)on March 21,2019.展开更多
As a critical guanine nucleotide exchange factor(GEF) regulating neurite outgrowth, Trio coordinates multiple processes of cytoskeletal dynamics through activating Rac1, Cdc42 and RhoA small GTPases by two GEF domains...As a critical guanine nucleotide exchange factor(GEF) regulating neurite outgrowth, Trio coordinates multiple processes of cytoskeletal dynamics through activating Rac1, Cdc42 and RhoA small GTPases by two GEF domains, but the in vivo roles of these GEF domains and corresponding downstream effectors have not been determined yet. We established multiple lines of knockout mice and assessed the respective roles of Trio GEF domains and Rac1 in axon outgrowth. Knockout of total Trio in cerebellar granule neurons(CGNs) led to an impaired F-actin rearrangement of growth cone and hence a retarded neurite outgrowth. Such a retardation was reproduced by inhibition of GEF1 domain or knockdown of Cdc42 and restored apparently by introduction of active Cdc42. As Rac1 deficiency did not affect the neurite outgrowth of CGNs, we suggested that Trio GEF1-mediated Cdc42 activation was required for neurite outgrowth. We established a GEF2-knockout line with deletion of all Trio isoforms except a cerebella-specific Trio8, a short isoform of Trio without GEF2 domain, and used this line as a GEF2-deficient animal model. The GEF2-deficient CGNs had a normal neurite outgrowth but abolished Netrin-1-promoted growth, without affecting Netrin-1 induced Rac1 activation. We thus suggested that Trio GEF1-mediated Cdc42 activation rather than Rac1 activation drives the F-actin dynamics necessary for neurite outgrowth, while GEF2 functions in Netrin-1-promoted neurite elongation. Our results delineated the distinct roles of Trio GEF domains in neurite outgrowth, which is instructive to understand the pathogenesis of clinical Trio-related neurodevelopmental disorders.展开更多
T cells are derived from progenitor thymocytes, of which only a minority receive the appropriate TCR signal, undergo positive selection and mature. Owing to the very short lifespan of thymocytes, the prerequisite for ...T cells are derived from progenitor thymocytes, of which only a minority receive the appropriate TCR signal, undergo positive selection and mature. Owing to the very short lifespan of thymocytes, the prerequisite for posi- tive selection is survival. TCR signal-induced Bcl-2 expression is believed to play a dominant role in the survival of positively selecting thymocytes, but how Bcl-2 is directly regulated is unknown. Here we report that the immediate early gene （IEG） c-Fos can stimulate the expression of Bcl-2, depending on a specific AP-l-binding site in the Bcl-2 promoter. In c-Fos transgenic （Fos-Tg） mice, c-Fos binds to this site and promotes the expression of Bcl-2. As a result, Fos-Tg thymocytes exhibited enhanced survival, and more mature single-positive （SP） thymocytes were generated, even on a unique TCR background. The TCR repertoire remained normal in Fos-Tg mice. Our results identified c-Fos as the mediator of the stimulatory effect of TCR signaling on Bcl-2 expression. Therefore, c-Fos, as an IEG, because of its early response ability, can quickly rescue the survival of short-lived thymocytes during positive selection. Our results provide novel insight into the mechanism regulating the survival of positively selecting thymocytes.展开更多
The key regulators and regeneration-associated genes involved in axonal regeneration of neurons after injury have not been clarified.In high-throughput sequencing,various factors influence the final sequencing results...The key regulators and regeneration-associated genes involved in axonal regeneration of neurons after injury have not been clarified.In high-throughput sequencing,various factors influence the final sequencing results,including the number and size of cells,the depth of sequencing,and the method of cell separation.There is still a lack of research on the detailed molecular expression profile during the regeneration of dorsal root ganglion neuron axon.In this study,we performed lase r-capture microdissection coupled with RNA sequencing on dorsal root ganglion neurons at 0,3,6,and 12 hours and 1,3,and 7 days after sciatic nerve crush in rats.We identified three stages after dorsal root ganglion injury:early(3-12 hours),pre-regeneration(1 day),and regeneration(3-7 days).Gene expression patterns and related function enrichment res ults showed that one module of genes was highly related to axonal regeneration.We verified the up-regulation of activating transcription factor 3(Atf3),Kruppel like factor 6(Klf6),AT-rich inte raction domain 5A(Arid5α),CAMP responsive element modulator(Crem),and FOS like 1,AP-1 transcription factor Subunit(Fosl1) in dorsal root ganglion neurons after injury.Suppressing these transcription factors(Crem,Arid5o,Fosl1 and Klf6) reduced axonal regrowth in vitro.As the hub transcription factor,Atf3 showed higher expression and activity at the preregeneration and regeneration stages.G protein-coupled estrogen receptor 1(Gper1),inte rleukin 12a(Il12α),estrogen receptor 1(ESR1),and interleukin 6(IL6) may be upstream factors that trigger the activation of Atf3 during the repair of axon injury in the early stage.Our study presents the detailed molecular expression profile during axonal regeneration of dorsal root ganglion neurons after peripheral nerve injury.These findings may provide reference for the clinical screening of molecular targets for the treatment of peripheral nerve injury.展开更多
N-ethyl-N-nitrosourea （ENU） mutagenesis has led to the elucidation of several regulator genes for melanocyte and skin development. Here we characterized a mutant from ENU mutagenesis with similar phenotype as that o...N-ethyl-N-nitrosourea （ENU） mutagenesis has led to the elucidation of several regulator genes for melanocyte and skin development. Here we characterized a mutant from ENU mutagenesis with similar phenotype as that of Splotch mutant, including exencephaly, spina bifida and abnormal limbs in homozygotes as well as white belly spotting and occasionally loop-tail in heterozygotes. This novel mutant was named as SpxG. Through genome-wide linkage analysis in backcross progenies with microsatellite markers, the SpxG was confined to a region between DIMIT415 and DIMIT7 on chromosome 1, where notable Pax3 gene was located. Direct sequencing revealed that SpxG carried a nucleotide A894G missense transition in exon 6 of Pax3 gene that resulted in Asn to Asp substitution at amino acid 269 within the highly-conserved homeodomain （HD） DNA recognition module, which was the first point mutation found in this domain in mice. This N269D mutation impaired the transactivation capacity of Pax3 protein, but exerted no effect on Pax3 protein translation. The characterization of the new mutation expanded our understanding the transactivation and DNA-binding structure of Pax3 protein.展开更多
Neurotrophic factors,particularly nerve growth factor,enhance neuronal regeneration.However,the in vivo applications of nerve growth factor are largely limited by its intrinsic disadvantages,such as its short biologic...Neurotrophic factors,particularly nerve growth factor,enhance neuronal regeneration.However,the in vivo applications of nerve growth factor are largely limited by its intrinsic disadvantages,such as its short biological half-life,its contribution to pain response,and its inability to cross the blood-brain barrier.Considering that let-7(human miRNA)targets and regulates nerve growth factor,and that let-7 is a core regulator in peripheral nerve regeneration,we evaluated the possibilities of let-7 application in nerve repair.In this study,anti-let-7a was identified as the most suitable let-7 family molecule by analyses of endogenous expression and regulatory relationship,and functional screening.Let-7a antagomir demonstrated biosafety based on the results of in vivo safety assessments and it entered into the main cell types of the sciatic nerve,including Schwann cells,fibroblasts and macrophages.Use of hydrogel effectively achieved controlled,localized,and sustained delivery of let-7a antagomir.Finally,let-7a antagomir was integrated into chitosan conduit to construct a chitosan-hydrogel scaffold tissue-engineered nerve graft,which promoted nerve regeneration and functional recovery in a rat model of sciatic nerve transection.Our study provides an experimental basis for potential in vivo application of let-7a.展开更多
Myosin light chain kinases （MLCK） phosphorylate the regulatory light chain of myosin II in thick filaments and bind to F-actin-containing thin filaments with high affinity. The ability of short myosin light chain ki...Myosin light chain kinases （MLCK） phosphorylate the regulatory light chain of myosin II in thick filaments and bind to F-actin-containing thin filaments with high affinity. The ability of short myosin light chain kinase （S-MLCK） to bind F-actin is structurally attributed to the DFRXXL regions in its N-terminus. The long myosin light chain kinase （L-MLCK） has two additional DFRXXL motifs and six Ig-like modules in its N-terminal extension. The six Ig-like modules are capable of binding to stress fibers independently. Our results from the imaging analysis demonstrated that the first two intact Ig-like modules （2Ig） in N-terminal extension of L-MLCK is the minimal binding module required for microfilament binding. Binding assay confirmed that F-actin was able to bind 2Ig. Stoichiometries of 2Ig peptide were similar for myofilament or pure F-actin. The binding affinities were slightly lower than 5DFRXXL peptide as reported previously. Similar to DFRXXL peptides, the 2Ig peptide also caused efficient F-actin bundle formation in vitro. In the living cell, over-expression of 2Ig fragment increased ＂spike＂-like protrusion formation with over-bundled F-actin. Our results suggest that L-MLCK may act as a potent F-actin bundling protein via its DFRXXL region and the 2Ig region, implying that L-MLCK plays a role in cytoskeleton organization.展开更多
Dear Editor,The peripheral nervous system(PNS)regenerates more easily after injury than the central nervous system(CNS)[1].Sensory neurons in the L4–L6 dorsal root ganglia(DRGs)extend axons to form the sciatic nerve ...Dear Editor,The peripheral nervous system(PNS)regenerates more easily after injury than the central nervous system(CNS)[1].Sensory neurons in the L4–L6 dorsal root ganglia(DRGs)extend axons to form the sciatic nerve along with motor axons.The DRG neuron is one of the exceptional mature neurons whose axons can regenerate after injury.展开更多
基金supported by the National Natural Science Foundation of China(82171136 and 92368110 to G.W.,82201291 to G.-J.Z.,82192861 to Z.X.,81970884 and 82192862 to X.G.)the Natural Science Foundation of Jiangsu Province(BK20220188 to Q.L.,BK20220189 to G.-J.Z.)the Fundamental Research Funds for the Central Universities(021414380533 to G.W.).
文摘Hearing relies on the structural and functional integrity of cochlear hair cells,particularly their apical F-actin-filled stereocilia.Phospholipid scramblases are important for maintaining membrane asymmetry,but their roles in the stereocilia and auditory functions are not fully understood.Here,we identify Plscr5 as a downstream target of the transcription factor POU4F3 essential for hair cell function,whose mutation causes human DFNA15 deafness.Plscr5 knockout mice exhibit progressive hearing loss due to stereocilia degeneration and hair cell loss.Functional analyses reveal that PLSCR5 contributes to phosphatidylserine externalization in hair cell apical membranes,particularly in inner hair cells,and is important for outer hair cell and stereocilia maintenance.Our findings highlight PLSCR5 as an important downstream effector of POU4F3 and regulator of phosphatidylserine externalization and membrane dynamics required for auditory functions.
基金supported by the National Key R&D Program of China(No.2022YFA1303600 and No.2023YFC2306800)the National Natural Science Foundation of China(No.82372235 and No.82272315)the Sanming Project of Medicine in Shenzhen(No.SZSM202311032).
文摘The persistence of covalently closed circular DNA(cccDNA)in hepatitis B virus(HBV)-infected hepatocytes remains a major obstacle to effective antiviral treatment.Understanding the molecular mechanisms regulating HBV cccDNA transcription is essential for developing novel therapeutic strategies.In this study,we investigated the role of RNA binding motif protein 25(RBM25)in HBV replication,focusing on its interaction with cccDNA and its regulation of host transcription factors.The results demonstrated that RBM25 knockdown markedly inhibited HBV replication,reducing levels of HBV DNA,hepatitis B e antigen(HBeAg),hepatitis B surface antigen(HBsAg),HBV RNA,and L-HBs in HBV-replicating and infected cell models.Consistent results were observed in a mouse model hydrodynamically injected with 1.2HBV plasmid.Conversely,RBM25 overexpression significantly enhanced HBV replication.Mechanistically,RBM25 promoted HBV promoter activities by binding to cccDNA through its RE/RD and PWI domains.This effect was mediated by increased Yin Yang 1(YY1)expression,which enhanced acetylation of cccDNA-bound histones,promoting HBV transcription.Furthermore,RBM25 expression was upregulated and translocated to the nucleus following core protein expression and accumulation,while overexpression of RBM25 promoted core protein degradation.In conclusion,this study demonstrates that RBM25 is a novel host factor that enhances HBV replication by upregulating YY1-dependent transcriptional activation of cccDNA.It also reveales a reciprocal regulatory mechanism between the HBV core protein and RBM25,which helps sustain HBV replication.
基金supported by grants from the National Key R&D Program of China(2019YFA0801603)the Guangdong High Level Innovation Research Institute(2021B0909050004)+2 种基金the National Natural Science Foundation of China(32330044,32170951,82201615,and 82101393)the Natural Science Foundation of Jiangsu Province(BK20201255 and BK20210008)the Fundamental Research Funds for the Central Universities(021414380533).
文摘Accurate timing of myelination is crucial for the proper functioning of the central nervous system. Here, we identified a de novo heterozygous mutation in TMEM63A (c.1894G>A;p. Ala632Thr) in a 7-year-old boy exhibiting hypomyelination. A Ca2+ influx assay suggested that this is a loss-of-function mutation. To explore how TMEM63A deficiency causes hypomyelination, we generated Tmem63a knockout mice. Genetic deletion of TMEM63A resulted in hypomyelination at postnatal day 14 (P14) arising from impaired differentiation of oligodendrocyte precursor cells (OPCs). Notably, the myelin dysplasia was transient, returning to normal levels by P28. Primary cultures of Tmem63a^(−/−) OPCs presented delayed differentiation. Lentivirus-based expression of TMEM63A but not TMEM63A_A632T rescued the differentiation of Tmem63a^(−/−) OPCs in vitro and myelination in Tmem63a^(−/−) mice. These data thus support the conclusion that the mutation in TMEM63A is the pathogenesis of the hypomyelination in the patient. Our study further demonstrated that TMEM63A-mediated Ca^(2+) influx plays critical roles in the early development of myelin and oligodendrocyte differentiation.
基金supported by The Beljanski Foundation(to JY)and Military Laboratory Animal Fund(Grant No.SYDW[2017]15to TF)。
文摘Objective:Herbal medicine is an important therapeutic option for benign prostatic hyperplasia(BPH),a common disease in older men that can seriously affect their quality of life.Currently,it is crucial to develop agents with strong efficacy and few side effects.Herein we investigated the effects of the extract of Rauwolfia vomitoria,a shrub grown in West Africa,on BPH.Methods:Rats with testosterone-induced BPH were treated with R.vomitoria.Prostates were histologically analyzed by Hematoxylin and eosin staining.Proliferation index and the expression levels of androgen receptor and its associated proteins were quantified through immunohistochemistry and immunoblotting.Androgen receptor target genes were examined by quantitative real-time polymerase chain reaction.The sperm count and body weight of rats were also measured.Results:The oral administration of R.vomitoria extract significantly reduced the prostate weight and prostate weight index in BPH rats,supported by the decreased thickness of the prostate epithelial layer and increased lumen size.Similar effects were observed in the BPH rats treated with the reference drug,finasteride.R.vomitoria extract significantly reduced the testosterone-induced proliferation markers,including proliferating cell nuclear antigen and cyclin D1,in the prostate glands of BPH rats;it also reduced levels of androgen receptor,its associated protein steroid 5 a-reductase 1 and its downstream target genes(FK506-binding protein 5 and matrix metalloproteinase 2).Notably,compared with the finasteride group,R.vomitoria extract did not significantly reduce sperm count.Conclusion:R.vomitoria suppresses testosterone-induced BPH development.Due to its milder side effects,R.vomitoria could be a promising therapeutic agent for BPH.
基金supported by the National Natural Science Foundation of China(82171136 and 81970888 to G.W.,32330044 to Y.S.S.)Fundamental Research Funds for the Central Universities(021414380533toG.W.).
文摘Sound transmission occurs in the cochlea,a complex and ingenious subdivision in the inner ear.The structure of the cochlea develops structurally and functionally by the time before two postnatal weeks(the time of hearing onset)in mice(Geal-Dor et al.,1993).Greater epithelial ridge(GER,also known as Kolliker's organ)is a transient cochlear structure containing a group of columnar epithelial supporting cells surrounding the inner hair cells(IHCs).
基金the National Key R&D Program of China(2021YFA0805802 to D.C.)the National Natural Science Foundation of China(31971092 and 32171156 to D.C.)Some strains were provided by the Caenorhabditis Genetics Center(CGC),which is funded by NIHOffice of Research Infrastructure Programs(P40 OD010440).
文摘The highly conserved target of rapamycin(TOR)pathway plays an important role in aging across species.Previous studies have established that inhibition of the TOR complex 1(TORC1)significantly extends lifespan in Caenorhabditis elegans.However,it has not been clear whether TORC1 perturbation affects aging in a spatiotemporal manner.Here,we apply the auxin-inducible degradation tool to knock down endogenous DAF-15,the C.elegans ortholog of regulatory associated protein of TOR(Raptor),to characterize its roles in aging.Global or tissue-specific inhibition of DAF-15 during development results in various growth defects,whereas neuron-specific knockdown of DAF-15 during adulthood significantly extends lifespan and healthspan.The neuronal DAF-15 deficiency-induced longevity requires the intestinal activities of DAF-16/FOXO and PHA-4/FOXA transcription factors,as well as the AAK-2/AMP-activated protein kinaseαcatalytic subunit.Transcriptome profiling reveals that the neuronal DAF-15 knockdown promotes the expression of genes involved in protection.These findings define the tissue-specific roles of TORC1 in healthy aging and highlight the importance of neuronal modulation of aging.
基金supported by the National Natural Science Foundation of China(82171136 and 92368110 to G.W.,82201291 to G.-J.Z.,82171145 to X.Q.,81870721 to J.C.,and 81970884 and 82192862 to X.G.)Natural Science Foundation of Jiangsu Province(BK20220189to G.-J.Z.and BK20220188 to Q.L.)+1 种基金Special Foundation for Health Science and Technology Development of Nanjing(YKK21109 to G.-J.Z.)the Clinical Research Foundation of Drum Tower Hospital affiliated to Nanjing University Medical School(2021-LCYJ-PY-04 to G.-J.Z.)。
文摘Accumulation of mutant proteins in cells can induce proteinopathies and cause functional damage to organs.Recently,the Cingulin(CGN)protein has been shown to maintain the morphology of cuticular plates of inner ear hair cells and a frameshift mutation in CGN causes autosomal dominant non-syndromic hearing loss.Here,we find that the mutant CGN proteins form insoluble aggregates which accumulate intracellularly and lead to cell death.Expression of the mutant CGN in the inner ear results in severe hair cell death and hearing loss in mice,resembling the auditory phenotype in human patients.Interestingly,a human-specific residue(V1112)in the neopeptide generated by the frameshift mutation is critical for the aggregation and cytotoxicity of the mutant human CGN.Moreover,the expression of heat shock factor 1(HSF1)decreases the accumulation of insoluble mutant CGN aggregates and rescues cell death.In summary,these findings identify mutant-specific toxic polypeptides as a disease-causing mechanism of the deafness mutation in CGN,which can be targeted by the expression of the cell chaperone response regulator HSF1.
基金National Key R&D Program of China(2022YFC2703400 to Y.G.Y.)National Natural Science Foundation of China(82001209 to S.S.D.,82271904 and 82070914 to Y.G.Y.)+2 种基金Shanghai Municipal Commission of Health and Family Planning(20204Y0451 to S.S.D.)Shanghai Scientific and Technological Innovation Action Plan(20YF1440600 to S.S.D.)Shanghai Natural Science Foundation of China(21ZR1452700 to Y.K.Z.)。
文摘Netrin-G2 is a membrane-anchored protein known to play critical roles in neuronal circuit development and synaptic organization.In this study,we identify compound heterozygous mutations of c.547delC p.(Arg183Alafs*186)and c.605G>A,p.(Trp202X)in NTNG2 causing a syndrome exhibiting developmenta delay,intellectual disability,hypotonia,and facial dysmorphism.To elucidate the underlying cellular and molecular mechanisms,CRISPR-Cas9 technology is employed to generate a knock-in mouse mode expressing the R183Afs and W202X mutations.We report that the Ntng2^(R183Afs/W202X)mice exhibit hypo tonia and impaired learning and memory.We find that the levels of CaMKII and p-GluA1^(Ser831)are decreased,and excitatory postsynaptic transmission and long-term potentiation are impaired.To increase the activity of CaMKII,the mutant mice receive intraperitoneal injections of DCP-LA,a CaMKII agonist,and show improved cognitive function.Together,our findings reveal molecular mechanisms of how NTNG2deficiency leads to impairments of cognitive ability and synaptic plasticity.
文摘In mammals,the neonatal heart can regenerate upon injury within a short time after birth,while adults lose this ability.Metabolic reprogramming has been demonstrated to be critical for cardiomyocyte proliferation in the neonatal heart.Here,we reveal that cardiac metabolic reprogramming could be regulated by altering global protein lactylation.By performing 4D label-free proteomics and lysine lactylation(Kla)omics analyses in mouse hearts at postnatal days 1,5,and 7,2297 Kla sites from 980 proteins are identified,among which 1262 Kla sites from 409 proteins are quantified.Functional clustering analysis reveals that the proteins with altered Kla sites are mainly involved in metabolic processes.The expression and Kla levels of proteins in glycolysis show a positive correlation while a negative correlation in fatty acid oxidation.Furthermore,we verify the Kla levels of several differentially modified proteins,including ACAT1,ACADL,ACADVL,PFKM,PKM,and NPM1.Overall,our study reports a comprehensive Kla map in the neonatal mouse heart,which will help to understand the regulatory network of metabolic reprogramming and cardiac regeneration.
基金supported by the National Natural Science Foundation of China(82271645)National Key Research and Development Program of China(2021YFC2700200 to F.S.)。
文摘Meiosis is a highly complex process significantly influenced by transcriptional regulation.However,studies on the mechanisms that govern transcriptomic changes during meiosis,especially in prophase I,are limited.Here,we performed single-cell ATAC-seq of human testis tissues and observed reprogramming during the transition from zygotene to pachytene spermatocytes.This event,conserved in mice,involved the deactivation of genes associated with meiosis after reprogramming and the activation of those related to spermatogenesis before their functional onset.Furthermore,we identified 282 transcriptional regulators(TRs)that underwent activation or deactivation subsequent to this process.Evidence suggested that physical contact signals from Sertoli cells may regulate these TRs in spermatocytes,while secreted ENHO signals may alter metabolic patterns in these cells.Our results further indicated that defective transcriptional reprogramming may be associated with non-obstructive azoospermia(NOA).This study revealed the importance of both physical contact and secreted signals between Sertoli cells and germ cells in meiotic progression.
文摘Looking back a decade ago when I decided to use ＂model animal＂ to name our newly established institute, my outrageous boldness can only be described by the old Chinese slang, ＂newborn calf could never sense the danger of tiger＂. Happily, my courageous belief, along with the hard work of my colleagues at Model Animal Research Center of Nanjing University, paid off eventually. We have witnessed the great progress in this research field in China in the past 10 years. This issue of Science China Life Sciences samplings some of these accomplishments.
基金supported by the National Natural Science Funding of China (31272311 and 31330034 to M.S.Z.)
文摘Several factors have been implicated in obesity-related hypertension, but the genesis of the hypertension is largely unknown. In this study, we found a significantly upregulated expression of CPI-17(C-kinasepotentiated protein phosphatase 1 inhibitor of 17 kDa) and protein kinase C(PKC) isoforms in the vascular smooth muscles of high-fat diet(HFD)-fed obese mice. The obese wild-type mice showed a significant elevation of blood pressure and enhanced calcium-sensitized contraction of vascular smooth muscles. However, the obese CPI-17-deficient mice showed a normotensive blood pressure, and the calcium-sensitized contraction was consistently reduced. In addition, the mutant muscle displayed an abolished responsive force to a PKC activator and a 30%-50% reduction in both the initial peak force and sustained force in response to various G protein-coupled receptor(GPCR) agonists. Our observations showed that CPI-17-mediated calcium sensitization is mediated through a GPCR/PKC/CPI-17/MLCP/RLC signaling pathway. We therefore propose that the upregulation of CPI-17-mediated calcium-sensitized vasocontraction by obesity contributes to the development of obesity-related hypertension.
基金This study was supported by the National Key Basic Research Program of China,No.2017YFA0104701(to XSG)the National Natural Science Foundation of China,No.31730031(to XSG),81870975(to SLZ)+1 种基金Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)(to XSG)the Natural Science Foundation of Jiangsu Province,No.BK20202013(to XSG).
文摘Recovery from injury to the peripheral nervous system is different from that of the central nervous system in that it can lead to gene reprogramming that can induce the expression of a series of regeneration-associated genes.This eventually leads to axonal regeneration of injured neurons.Although some regeneration-related genes have been identified,the regulatory network underlying axon regeneration remains largely unknown.To explore the regulator of axon regeneration,we performed RNA sequencing of lumbar L4 and L5 dorsal root ganglion(DRG)neurons at different time points(0,3,6,12 hours,1,3 and 7 days)after rat sciatic nerve crush.The isolation of neurons was carried out by laser capture microscopy combined with NeuN immunofluorescence staining.We found 1228 differentially expressed genes in the injured sciatic nerve tissue.The hub genes within these differentially expressed genes include Atf3,Jun,Myc,Ngf,Fgf2,Ezh2,Gfap and Il6.We verified that the expression of the enhancer of zeste homologue 2 gene(Ezh2)was up-regulated in DRG neurons after injury,and this up-regulation differed between large-and small-sized dorsal root ganglion neurons.To investigate whether the up-regulation of Ezh2 impacts axonal regeneration,we silenced Ezh2 with siRNA in cultured DRG neurons and found that the growth of the newborn axons was repressed.In our investigation into the regulatory network of Ezh2 by interpretive phenomenal analysis,we found some regulators of Ezh2(including Erk,Il6 and Hif1a)and targets(including Atf3,Cdkn1a and Smad1).Our findings suggest that Ezh2,as a nerve regeneration-related gene,participates in the repair of the injured DRG neurons,and knocking down the Ezh2 in vitro inhibits the axonal growth of DRG neurons.All the experimental procedures approved by the Administration Committee of Experimental Animals of Jiangsu Province of China(approval No.S20191201-201)on March 21,2019.
基金supported by grants from the National Natural Science Foundation of China (31272311 and 31330034) to M.S.Z.
文摘As a critical guanine nucleotide exchange factor(GEF) regulating neurite outgrowth, Trio coordinates multiple processes of cytoskeletal dynamics through activating Rac1, Cdc42 and RhoA small GTPases by two GEF domains, but the in vivo roles of these GEF domains and corresponding downstream effectors have not been determined yet. We established multiple lines of knockout mice and assessed the respective roles of Trio GEF domains and Rac1 in axon outgrowth. Knockout of total Trio in cerebellar granule neurons(CGNs) led to an impaired F-actin rearrangement of growth cone and hence a retarded neurite outgrowth. Such a retardation was reproduced by inhibition of GEF1 domain or knockdown of Cdc42 and restored apparently by introduction of active Cdc42. As Rac1 deficiency did not affect the neurite outgrowth of CGNs, we suggested that Trio GEF1-mediated Cdc42 activation was required for neurite outgrowth. We established a GEF2-knockout line with deletion of all Trio isoforms except a cerebella-specific Trio8, a short isoform of Trio without GEF2 domain, and used this line as a GEF2-deficient animal model. The GEF2-deficient CGNs had a normal neurite outgrowth but abolished Netrin-1-promoted growth, without affecting Netrin-1 induced Rac1 activation. We thus suggested that Trio GEF1-mediated Cdc42 activation rather than Rac1 activation drives the F-actin dynamics necessary for neurite outgrowth, while GEF2 functions in Netrin-1-promoted neurite elongation. Our results delineated the distinct roles of Trio GEF domains in neurite outgrowth, which is instructive to understand the pathogenesis of clinical Trio-related neurodevelopmental disorders.
文摘T cells are derived from progenitor thymocytes, of which only a minority receive the appropriate TCR signal, undergo positive selection and mature. Owing to the very short lifespan of thymocytes, the prerequisite for posi- tive selection is survival. TCR signal-induced Bcl-2 expression is believed to play a dominant role in the survival of positively selecting thymocytes, but how Bcl-2 is directly regulated is unknown. Here we report that the immediate early gene （IEG） c-Fos can stimulate the expression of Bcl-2, depending on a specific AP-l-binding site in the Bcl-2 promoter. In c-Fos transgenic （Fos-Tg） mice, c-Fos binds to this site and promotes the expression of Bcl-2. As a result, Fos-Tg thymocytes exhibited enhanced survival, and more mature single-positive （SP） thymocytes were generated, even on a unique TCR background. The TCR repertoire remained normal in Fos-Tg mice. Our results identified c-Fos as the mediator of the stimulatory effect of TCR signaling on Bcl-2 expression. Therefore, c-Fos, as an IEG, because of its early response ability, can quickly rescue the survival of short-lived thymocytes during positive selection. Our results provide novel insight into the mechanism regulating the survival of positively selecting thymocytes.
基金supported by the National Natural Science Foundation of China,Nos. 31730031 and 32130060the National Major Project of Research and Development,No. 2017YFA0104700the Natural Science Foundation of Jiangsu Province,No. BK20202013 (all to XSG)。
文摘The key regulators and regeneration-associated genes involved in axonal regeneration of neurons after injury have not been clarified.In high-throughput sequencing,various factors influence the final sequencing results,including the number and size of cells,the depth of sequencing,and the method of cell separation.There is still a lack of research on the detailed molecular expression profile during the regeneration of dorsal root ganglion neuron axon.In this study,we performed lase r-capture microdissection coupled with RNA sequencing on dorsal root ganglion neurons at 0,3,6,and 12 hours and 1,3,and 7 days after sciatic nerve crush in rats.We identified three stages after dorsal root ganglion injury:early(3-12 hours),pre-regeneration(1 day),and regeneration(3-7 days).Gene expression patterns and related function enrichment res ults showed that one module of genes was highly related to axonal regeneration.We verified the up-regulation of activating transcription factor 3(Atf3),Kruppel like factor 6(Klf6),AT-rich inte raction domain 5A(Arid5α),CAMP responsive element modulator(Crem),and FOS like 1,AP-1 transcription factor Subunit(Fosl1) in dorsal root ganglion neurons after injury.Suppressing these transcription factors(Crem,Arid5o,Fosl1 and Klf6) reduced axonal regrowth in vitro.As the hub transcription factor,Atf3 showed higher expression and activity at the preregeneration and regeneration stages.G protein-coupled estrogen receptor 1(Gper1),inte rleukin 12a(Il12α),estrogen receptor 1(ESR1),and interleukin 6(IL6) may be upstream factors that trigger the activation of Atf3 during the repair of axon injury in the early stage.Our study presents the detailed molecular expression profile during axonal regeneration of dorsal root ganglion neurons after peripheral nerve injury.These findings may provide reference for the clinical screening of molecular targets for the treatment of peripheral nerve injury.
基金supported by the National Basic Research Program of China(No.2007CB947301)the National Natural Science Foundation of China(No.30800613)Pujiang Talent(No.08PJ1407200)
文摘N-ethyl-N-nitrosourea （ENU） mutagenesis has led to the elucidation of several regulator genes for melanocyte and skin development. Here we characterized a mutant from ENU mutagenesis with similar phenotype as that of Splotch mutant, including exencephaly, spina bifida and abnormal limbs in homozygotes as well as white belly spotting and occasionally loop-tail in heterozygotes. This novel mutant was named as SpxG. Through genome-wide linkage analysis in backcross progenies with microsatellite markers, the SpxG was confined to a region between DIMIT415 and DIMIT7 on chromosome 1, where notable Pax3 gene was located. Direct sequencing revealed that SpxG carried a nucleotide A894G missense transition in exon 6 of Pax3 gene that resulted in Asn to Asp substitution at amino acid 269 within the highly-conserved homeodomain （HD） DNA recognition module, which was the first point mutation found in this domain in mice. This N269D mutation impaired the transactivation capacity of Pax3 protein, but exerted no effect on Pax3 protein translation. The characterization of the new mutation expanded our understanding the transactivation and DNA-binding structure of Pax3 protein.
基金supported by the National Natural Science Foundation of China,No.31970968(to SYL)the Collegiate Natural Science Foundation of Jiangsu Province,No.16KJA310005(to SYL)+1 种基金Priority Academic Program Development of Jiangsu Higher Education Institutions[PAPD]the Natural Science Foundation of Jiangsu Province,No.BK20200976(to XHW).
文摘Neurotrophic factors,particularly nerve growth factor,enhance neuronal regeneration.However,the in vivo applications of nerve growth factor are largely limited by its intrinsic disadvantages,such as its short biological half-life,its contribution to pain response,and its inability to cross the blood-brain barrier.Considering that let-7(human miRNA)targets and regulates nerve growth factor,and that let-7 is a core regulator in peripheral nerve regeneration,we evaluated the possibilities of let-7 application in nerve repair.In this study,anti-let-7a was identified as the most suitable let-7 family molecule by analyses of endogenous expression and regulatory relationship,and functional screening.Let-7a antagomir demonstrated biosafety based on the results of in vivo safety assessments and it entered into the main cell types of the sciatic nerve,including Schwann cells,fibroblasts and macrophages.Use of hydrogel effectively achieved controlled,localized,and sustained delivery of let-7a antagomir.Finally,let-7a antagomir was integrated into chitosan conduit to construct a chitosan-hydrogel scaffold tissue-engineered nerve graft,which promoted nerve regeneration and functional recovery in a rat model of sciatic nerve transection.Our study provides an experimental basis for potential in vivo application of let-7a.
基金This work was supported by National Naturcal Science Foundation of China （No. 30470852）The National Gongguan Project of China （21001BA710B）.
文摘Myosin light chain kinases （MLCK） phosphorylate the regulatory light chain of myosin II in thick filaments and bind to F-actin-containing thin filaments with high affinity. The ability of short myosin light chain kinase （S-MLCK） to bind F-actin is structurally attributed to the DFRXXL regions in its N-terminus. The long myosin light chain kinase （L-MLCK） has two additional DFRXXL motifs and six Ig-like modules in its N-terminal extension. The six Ig-like modules are capable of binding to stress fibers independently. Our results from the imaging analysis demonstrated that the first two intact Ig-like modules （2Ig） in N-terminal extension of L-MLCK is the minimal binding module required for microfilament binding. Binding assay confirmed that F-actin was able to bind 2Ig. Stoichiometries of 2Ig peptide were similar for myofilament or pure F-actin. The binding affinities were slightly lower than 5DFRXXL peptide as reported previously. Similar to DFRXXL peptides, the 2Ig peptide also caused efficient F-actin bundle formation in vitro. In the living cell, over-expression of 2Ig fragment increased ＂spike＂-like protrusion formation with over-bundled F-actin. Our results suggest that L-MLCK may act as a potent F-actin bundling protein via its DFRXXL region and the 2Ig region, implying that L-MLCK plays a role in cytoskeleton organization.
基金the National Key Basic Research Program of China(2017YFA0104701)the National Natural Science Foundation of China(31730031,81571198,81870975,81971170,and 81671230)+1 种基金the Natural Science Foundation of Jiangsu Province(BK20202013)the Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘Dear Editor,The peripheral nervous system(PNS)regenerates more easily after injury than the central nervous system(CNS)[1].Sensory neurons in the L4–L6 dorsal root ganglia(DRGs)extend axons to form the sciatic nerve along with motor axons.The DRG neuron is one of the exceptional mature neurons whose axons can regenerate after injury.
