MicroRNAs （miRNAs） post-transcriptionally regulate gene expression by binding to target mRNAs with perfect or imperfect complementarity, recruiting an Argonaute （AGO） protein complex that usually results in degrad...MicroRNAs （miRNAs） post-transcriptionally regulate gene expression by binding to target mRNAs with perfect or imperfect complementarity, recruiting an Argonaute （AGO） protein complex that usually results in degradation or translational repression of the target mRNA. AGO proteins function as the Slicer enzyme in miRNA and small interfering RNA （siRNA） pathways involved in human physiological and pathophysiological processes, such as antiviral responses and disease formation. Although the past decade has witnessed rapid advancement in studies of AGO protein functions, to further elucidate the molecular mechanism of AGO proteins in cellular function and biochemical process is really a challenging area for researchers. In order to understand the molecular causes underlying the pathological processes, we mainly focus on five fundamental problems of AGO proteins, including evolution, functional domain, subcellular location, post-translational modification and protein-protein interactions. Our discussion highlight their roles in early diagnosis, disease prevention, drug target identification, drug response, etc.展开更多
As multipotent progenitor cells,mesenchymal stem cells(MSCs)can renew themselves and give rise to multiple lineages including osteoblastic,chondrogenic and adipogenic lineages.It’s previously shown that BMP9 is the m...As multipotent progenitor cells,mesenchymal stem cells(MSCs)can renew themselves and give rise to multiple lineages including osteoblastic,chondrogenic and adipogenic lineages.It’s previously shown that BMP9 is the most potent BMP and induces osteogenic and adipogenic differentiation of MSCs.However,the molecular mechanism through which BMP9 regulates MSC differentiation remains poorly understood.Emerging evidence indicates that noncoding RNAs,especially microRNAs,may play important roles in regulating MSC differentiation and bone formation.As highly conserved RNA binding proteins,Argonaute(AGO)proteins are essential components of the multi-protein RNA-induced silencing complexes(RISCs),which are critical for small RNA biogenesis.Here,we investigate possible roles of AGO proteins in BMP9-induced lineage-specific differentiation of MSCs.We first found that BMP9 upregulated the expression of Ago1,Ago2 and Ago3 in MSCs.By engineering multiplex siRNA vectors that express multiple siRNAs targeting individual Ago genes or all four Ago genes,we found that silencing individual Ago expression led to a decrease in BMP9-induced early osteogenic marker alkaline phosphatase(ALP)activity in MSCs.Furthermore,we demonstrated that simultaneously silencing all four Ago genes significantly diminished BMP9-induced osteogenic and adipogenic differentiation of MSCs and matrix mineralization,and ectopic bone formation.Collectively,our findings strongly indicate that AGO proteins and associated small RNA biogenesis pathway play an essential role in mediating BMP9-induced osteogenic differentiation of MSCs.展开更多
AGO蛋白家族(Argonaute protein family)是RNA诱导沉默复合物(RISC)的功能核心,参与小RNA介导的基因沉默.AGO蛋白由N末端、PAZ、MID和PIWI四个结构域组成.它和小RNA在植物中共同参与维持基因组的稳定、调控组织发育、DNA修复、对逆境的...AGO蛋白家族(Argonaute protein family)是RNA诱导沉默复合物(RISC)的功能核心,参与小RNA介导的基因沉默.AGO蛋白由N末端、PAZ、MID和PIWI四个结构域组成.它和小RNA在植物中共同参与维持基因组的稳定、调控组织发育、DNA修复、对逆境的适应性应答以及在RNA层面对入侵核酸(转基因和植物病毒)的免疫.植物AGO蛋白在胚胎发育,细胞分化和转座子的沉默中具有重要作用.本文运用生物信息学的方法,结合生物信息学两大门户网站,对植物AGO蛋白的分类、平均疏水性、净电荷、不稳定系数等进行预测.展开更多
为初步探究OsAGO家族在水稻抗病毒通路中的功能,对水稻OsAGO蛋白的基因组结构、系统发育关系、氨基酸序列及水稻瘤矮病毒(rice gall dwarf virus,RGDV)和南方水稻黑条矮缩病毒(southern rice black streaked dwarf virus,SRBSDV)侵染后...为初步探究OsAGO家族在水稻抗病毒通路中的功能,对水稻OsAGO蛋白的基因组结构、系统发育关系、氨基酸序列及水稻瘤矮病毒(rice gall dwarf virus,RGDV)和南方水稻黑条矮缩病毒(southern rice black streaked dwarf virus,SRBSDV)侵染后的转录组数据进行分析,同时采用实时荧光定量PCR(quantitative real-time PCR,qPCR)技术对这2种病毒侵染后OsAGO基因的相对表达量变化进行验证。结果表明,19个水稻OsAGO蛋白的外显子数量、内含子数量及编码区长度存在较大差异,且这19个OsAGO蛋白均匀分布在3个分支中;OsAGO蛋白PAZ结构域中与小RNA结合相关的YF(酪氨酸-苯丙氨酸)基序在OsAGO2、OsAGO3和OsAGO5中变成了YY(酪氨酸-酪氨酸),OsAGO蛋白PIWI结构域中与OsAGO蛋白切割活性相关的DDX(X代表H或D,即天冬氨酸-天冬氨酸-组氨酸/天冬氨酸)基序在OsAGO13中替换为LDH(亮氨酸-天冬氨酸-组氨酸)基序,而在OsAGO17中不包含YF基序且DDX基序替换为HDR(组氨酸-天冬氨酸-精氨酸)基序。RGDV侵染后OsAGO5和OsAGO12基因的转录组分析结果与qPCR结果一致,其中OsAGO5上调表达,OsAGO12下调表达;SRBSDV侵染后OsAGO1a、OsAGO1b、OsAGO1c、OsAGO1d和OsAGO4b基因的转录组分析结果与qPCR结果一致,均上调表达。表明大多数OsAGO均能响应RGDV和SRBSDV的侵染。展开更多
文摘MicroRNAs （miRNAs） post-transcriptionally regulate gene expression by binding to target mRNAs with perfect or imperfect complementarity, recruiting an Argonaute （AGO） protein complex that usually results in degradation or translational repression of the target mRNA. AGO proteins function as the Slicer enzyme in miRNA and small interfering RNA （siRNA） pathways involved in human physiological and pathophysiological processes, such as antiviral responses and disease formation. Although the past decade has witnessed rapid advancement in studies of AGO protein functions, to further elucidate the molecular mechanism of AGO proteins in cellular function and biochemical process is really a challenging area for researchers. In order to understand the molecular causes underlying the pathological processes, we mainly focus on five fundamental problems of AGO proteins, including evolution, functional domain, subcellular location, post-translational modification and protein-protein interactions. Our discussion highlight their roles in early diagnosis, disease prevention, drug target identification, drug response, etc.
基金The reported work was supported in part by research grants from the National Institutes of Health(CA226303 to TCH,and AR072731 to JY)the Chicago Biomedical Consortium with support from the Searle Funds at The Chicago Community Trust(RRR),and the Scoliosis Research Society(TCH and MJL)+2 种基金WW was supported by the Medical Scientist Training Program of the National Institutes of Health(T32 GM007281)This project was also supported in part by The University of Chicago Cancer Center Support Grant(P30CA014599)the National Center for Advancing Translational Sciences(NCATS)of the National Institutes of Health(NIH)through Grant Number 5UL1TR002389-02 that funds the Institute for Translational Medicine(ITM).TCH was supported by the Mabel Green Myers Research Endowment Fund and The University of Chicago Orthopaedics Alumni Fund.
文摘As multipotent progenitor cells,mesenchymal stem cells(MSCs)can renew themselves and give rise to multiple lineages including osteoblastic,chondrogenic and adipogenic lineages.It’s previously shown that BMP9 is the most potent BMP and induces osteogenic and adipogenic differentiation of MSCs.However,the molecular mechanism through which BMP9 regulates MSC differentiation remains poorly understood.Emerging evidence indicates that noncoding RNAs,especially microRNAs,may play important roles in regulating MSC differentiation and bone formation.As highly conserved RNA binding proteins,Argonaute(AGO)proteins are essential components of the multi-protein RNA-induced silencing complexes(RISCs),which are critical for small RNA biogenesis.Here,we investigate possible roles of AGO proteins in BMP9-induced lineage-specific differentiation of MSCs.We first found that BMP9 upregulated the expression of Ago1,Ago2 and Ago3 in MSCs.By engineering multiplex siRNA vectors that express multiple siRNAs targeting individual Ago genes or all four Ago genes,we found that silencing individual Ago expression led to a decrease in BMP9-induced early osteogenic marker alkaline phosphatase(ALP)activity in MSCs.Furthermore,we demonstrated that simultaneously silencing all four Ago genes significantly diminished BMP9-induced osteogenic and adipogenic differentiation of MSCs and matrix mineralization,and ectopic bone formation.Collectively,our findings strongly indicate that AGO proteins and associated small RNA biogenesis pathway play an essential role in mediating BMP9-induced osteogenic differentiation of MSCs.
文摘AGO蛋白家族(Argonaute protein family)是RNA诱导沉默复合物(RISC)的功能核心,参与小RNA介导的基因沉默.AGO蛋白由N末端、PAZ、MID和PIWI四个结构域组成.它和小RNA在植物中共同参与维持基因组的稳定、调控组织发育、DNA修复、对逆境的适应性应答以及在RNA层面对入侵核酸(转基因和植物病毒)的免疫.植物AGO蛋白在胚胎发育,细胞分化和转座子的沉默中具有重要作用.本文运用生物信息学的方法,结合生物信息学两大门户网站,对植物AGO蛋白的分类、平均疏水性、净电荷、不稳定系数等进行预测.
