Posttranscriptional mechanisms have a critical role in the overall outcome of gene expression. These mechanisms are especially relevant in protozoa from the genus Trypanosoma, which is composed by death threatening pa...Posttranscriptional mechanisms have a critical role in the overall outcome of gene expression. These mechanisms are especially relevant in protozoa from the genus Trypanosoma, which is composed by death threatening parasites affecting people in Sub-saharan Africa or in the Americas. In these parasites the classic view of regulation of transcription initiation to modulate the products of a given gene cannot be applied. This is due to the presence of transcription start sites that give rise to long polycistronic units that need to be processed costranscriptionally by trans-splicing and polyadenylation to give mature monocistronic mRNAs. Posttranscriptional mechanisms such as mRNA degradation and translational repression are responsible for the final synthesis of the required protein products. In this context, RNA-binding proteins(RBPs) in trypanosomes have a relevant role as modulators of mRNA abundance and translational repression by associating to the 3' untranslated regions in mRNA. Many different RBPs have been proposed to modulate cohorts of mRNAs in trypanosomes. However, the current understanding of their functions lacks a dynamic view on the different steps at which these RBPs are regulated. Here, we discuss different evidences to propose regulatory events for different RBPs in these parasites. These events vary from regulated developmental expression, to biogenesis of cytoplasmic ribonucleoprotein complexes in the nucleus, and condensation of RBPs and mRNA into large cytoplasmic granules. Finally, we discuss how newly identified posttranslational modifications of RBPs and mRNA metabolism-related proteins could have an enormous impact on the modulation of m RNA abundance. To understand these modifications is especially relevant in these parasites due to the fact that the enzymes involved could be interesting targets for drug therapy.展开更多
Controlled gene regulation during gamete development is vital for maintaining reproductive potential. During the complex process of mammalian spermatogenesis, male germ cells experience extended periods of the inactiv...Controlled gene regulation during gamete development is vital for maintaining reproductive potential. During the complex process of mammalian spermatogenesis, male germ cells experience extended periods of the inactive transcription despite heavy translational requirements for continued growth and differentiation. Hence, spermatogenesis is highly reliant on mechanisms of posttranscriptional regulation of gene expression, facilitated by RNA binding proteins （RBPs）, which remain abundantly expressed throughout this process. One such group of proteins is the Musashi family, previously identified as critical regulators of testis germ cell development and meiosis in Drosophila, and also shown to be vital to sperm development and reproductive potential in the mouse. This review describes the role and function of RBPs our recent knowledge of the Musashi proteins in spermatogenesis. within the scope of male germ cell development, focusing on The functional mechanisms utilized by RBPs within the cell are outlined in depth, and the significance of sub-cellular localization and stage-specific expression in relation to the mode and impact of posttranscriptional regulation is also highlighted. We emphasize the historical role of the Musashi family of RBPs in stem cell function and cell fate determination, as originally characterized in Drosophila and Xenopus, and conclude with our current understanding of the differential roles and functions of the mammalian Musashi proteins, Musashi-1 and Musashi-2, with a primary focus on our findings in spermatogenesis. This review highlights both the essential contribution of RBPs to posttranscriptional regulation and the importance of the Musashi family as master regulators of male gamete development.展开更多
Accumulating evidence indicates that long non-coding RNAs(lncRNAs)can play a pivotal role in regulation of diverse cellular processes.In particular,lncRNAs can serve as master gene regulators at transcriptional and po...Accumulating evidence indicates that long non-coding RNAs(lncRNAs)can play a pivotal role in regulation of diverse cellular processes.In particular,lncRNAs can serve as master gene regulators at transcriptional and posttranscriptional levels,leading to tumorigenesis.In this review,we discuss latest developments in lncRNA-meditated gene expression at the post-transcriptional level,including gene splicing,mRNA stability,protein stability and nuclear trafficking.展开更多
目的:研究RNA结合基序单链相互作用蛋白3(RNA-binding motif,single-stranded-interacting protein 3,RBMS3)对胃癌细胞侵袭的影响,并探讨其可能的分子作用机制。方法:首先采用实时荧光定量PCR和蛋白质印迹法检测人正常胃黏膜上皮细胞GE...目的:研究RNA结合基序单链相互作用蛋白3(RNA-binding motif,single-stranded-interacting protein 3,RBMS3)对胃癌细胞侵袭的影响,并探讨其可能的分子作用机制。方法:首先采用实时荧光定量PCR和蛋白质印迹法检测人正常胃黏膜上皮细胞GES-1以及胃癌细胞MKN-28、MKN-45、NCI-N87和SGC-7901中RBMS3的表达水平。然后采用脂质体转染法将RBMS3过表达载体[RBMS3-pcDNA3.1(+)]转染至胃癌MKN-45和SGC-7901细胞中,同时设置空白对照组和空载体转染的阴性对照组。采用实时荧光定量PCR和蛋白质印迹法验证RBMS3过表达效果后,Transwell小室法检测细胞侵袭能力的变化,实时荧光定量PCR和蛋白质印迹法检测细胞中上皮-间质转化相关蛋白以及Wnt信号通路中β-连环蛋白(β-catenin)的表达水平变化。最后,用Wnt通路激动剂氯化锂(lithium chloride,LiCl)处理RBMS3过表达的胃癌MKN-45和SGC-7901细胞后,再次采用Transwell小室法检测细胞侵袭能力的变化。结果:与正常胃黏膜细胞相比,4种胃癌细胞中RBMS3 mRNA和蛋白的表达水平均明显降低(P值均<0.05)。RBMS3过表达质粒转染后,胃癌MKN-45和SGC-7901细胞中RBMS 3基因过表达,2种细胞的侵袭能力随之明显降低(P值均<0.05)。在RBMS3过表达的胃癌MKN-45和SGC-7901细胞中,N-钙黏蛋白(N-cadherin)和β-catenin表达水平均明显降低(P值均<0.05),而E-钙黏蛋白(E-cadherin)表达水平明显升高(P值均<0.05)。用LiCl处理RBMS3过表达的MKN-45和SGC-7901细胞后,RBMS3对2种细胞侵袭的抑制作用均被部分抵消(P值均<0.05)。结论:RBMS3可能通过阻滞Wnt/β-catenin信号通路,抑制人胃癌细胞的侵袭和上皮-间质转化。展开更多
基金Supported by The Agencia Nacional de Promoción Científica y Tecnológica(ANPCyT)to Alejandro Cassola
文摘Posttranscriptional mechanisms have a critical role in the overall outcome of gene expression. These mechanisms are especially relevant in protozoa from the genus Trypanosoma, which is composed by death threatening parasites affecting people in Sub-saharan Africa or in the Americas. In these parasites the classic view of regulation of transcription initiation to modulate the products of a given gene cannot be applied. This is due to the presence of transcription start sites that give rise to long polycistronic units that need to be processed costranscriptionally by trans-splicing and polyadenylation to give mature monocistronic mRNAs. Posttranscriptional mechanisms such as mRNA degradation and translational repression are responsible for the final synthesis of the required protein products. In this context, RNA-binding proteins(RBPs) in trypanosomes have a relevant role as modulators of mRNA abundance and translational repression by associating to the 3' untranslated regions in mRNA. Many different RBPs have been proposed to modulate cohorts of mRNAs in trypanosomes. However, the current understanding of their functions lacks a dynamic view on the different steps at which these RBPs are regulated. Here, we discuss different evidences to propose regulatory events for different RBPs in these parasites. These events vary from regulated developmental expression, to biogenesis of cytoplasmic ribonucleoprotein complexes in the nucleus, and condensation of RBPs and mRNA into large cytoplasmic granules. Finally, we discuss how newly identified posttranslational modifications of RBPs and mRNA metabolism-related proteins could have an enormous impact on the modulation of m RNA abundance. To understand these modifications is especially relevant in these parasites due to the fact that the enzymes involved could be interesting targets for drug therapy.
文摘Controlled gene regulation during gamete development is vital for maintaining reproductive potential. During the complex process of mammalian spermatogenesis, male germ cells experience extended periods of the inactive transcription despite heavy translational requirements for continued growth and differentiation. Hence, spermatogenesis is highly reliant on mechanisms of posttranscriptional regulation of gene expression, facilitated by RNA binding proteins （RBPs）, which remain abundantly expressed throughout this process. One such group of proteins is the Musashi family, previously identified as critical regulators of testis germ cell development and meiosis in Drosophila, and also shown to be vital to sperm development and reproductive potential in the mouse. This review describes the role and function of RBPs our recent knowledge of the Musashi proteins in spermatogenesis. within the scope of male germ cell development, focusing on The functional mechanisms utilized by RBPs within the cell are outlined in depth, and the significance of sub-cellular localization and stage-specific expression in relation to the mode and impact of posttranscriptional regulation is also highlighted. We emphasize the historical role of the Musashi family of RBPs in stem cell function and cell fate determination, as originally characterized in Drosophila and Xenopus, and conclude with our current understanding of the differential roles and functions of the mammalian Musashi proteins, Musashi-1 and Musashi-2, with a primary focus on our findings in spermatogenesis. This review highlights both the essential contribution of RBPs to posttranscriptional regulation and the importance of the Musashi family as master regulators of male gamete development.
基金This work was supported by NIH grant R01 CA154989(YM).
文摘Accumulating evidence indicates that long non-coding RNAs(lncRNAs)can play a pivotal role in regulation of diverse cellular processes.In particular,lncRNAs can serve as master gene regulators at transcriptional and posttranscriptional levels,leading to tumorigenesis.In this review,we discuss latest developments in lncRNA-meditated gene expression at the post-transcriptional level,including gene splicing,mRNA stability,protein stability and nuclear trafficking.
基金Research from the corresponding author’s laboratory was supported by grants from Merit-Review Award from US Department of Veterans Affairs and National Institutes of Health(NIH),USA(No.DK-57819,DK-61972,and DK-68491).
