Molecular mechanisms of RNAi-related factors involved in gene silencing

RNAi相关因子参与基因沉默的分子机制

基本信息

批准号：
16207011
负责人：
SIOMI Mikiko
金额：
$ 29.37万
依托单位：
The University of Tokushima
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

项目摘要

Fragile X syndrome is the most common cause of inherited mental retardation. Since after the discovery of the responsible gene, fmr1, for Fragile X, we have been trying to understand molecular mechanisms underlying fmrl gene function. Through the study, we found that fly genome contains a single gene highly similar to human fmr1, dfmr1, and that the protein product of dfmrl, dFMR1, is able to associate with one of RNAi factors, Argonaute (AGO). To elucidate the function of dFMR1 (eventually human FMR1), we thought that it is necessary to elucidate the molecular mechanisms underlying RNAi and its related pathways, and identify protein factors necessary for the processes. Results we obtained for the three years supported by KIBAN(A) are summarized below ;We found that AGO1 and AGO2 bind specifically with miRNA and siRNA, respectively, and function as Slicer in gene silencing mechanisms in Drosophila. We also showed that ATP is not required for RNAi reaction in vitro. It was also shown that AGO2 functions as siRNA duplex unwinder in RNAi (Miyoshi et al. Genes Dev 2005). Lately, we studied members of the Argonautes exclusively expressed in germline cells (AGO3, Aub, and Piwi) and found that they function in silencing selfish genes such as retrotransposons through associating with rasiRNAs originated from transcripts of retrotransposons in germlines (Saito et al. 2006, Gunawardane et al. 2007). We also proposed a 'rasiRNA biogenesis' model through our study (Gunawardane et al. 2007).

脆弱的X综合征是遗传性智力低下的最常见原因。自从发现负责的基因FMR1之后，对于脆弱的X，我们一直在尝试理解FMRL基因功能的分子机制。通过这项研究，我们发现FLY基因组包含一个与人FMR1，DFMR1高度相似的单个基因，并且DFMRL DFMR1的蛋白质产物能够与RNAi因子之一Argonaute（Ago）相关联（AGO）。为了阐明DFMR1（最终人FMR1）的功能，我们认为有必要阐明RNAi及其相关途径的分子机制，并确定该过程所需的蛋白质因子。下面总结了基班（A）支持的三年中获得的结果；我们发现AGO1和AGO2分别与miRNA和siRNA专门结合，并在果蝇中的基因沉默机制中充当切片。我们还表明，体外RNAi反应不需要ATP。还表明，AGO2在RNAi中充当siRNA双链螺旋体（Miyoshi等人Genes Dev 2005）。最近，我们研究了在种系细胞（AGO3，AUB和PIWI）中独家表达的Argonautes成员，发现它们在沉默的自私基因（例如逆转转座）中起作用，通过与rasirnas通过与rasirnas相关联，该rasirnas源自源自胶菌的转化转导（Saito等。，Gunawardane等人。我们还通过我们的研究提出了“ rasirna生物发生”模型（Gunawardane等，2007）。