The Control of Gene Expression by Eukaryotic RNase III

描述(申请人提供)：转录后调控已经成为一种有效的方法来控制基因表达的数量和质量。RNase III家族的双链RNA内切酶在多种基因表达途径中发挥重要作用：它们参与核糖体RNA前体的加工，参与剪接和rRNA代谢的小RNA的加工，以及microRNAs的加工。它们还参与了RNA干扰过程中小干扰RNA的生产。我们的长期目标是(I)详尽地鉴定由RNase III家族的真核成员控制的基因表达途径，(Ii)了解这些酶结合和切割dsRNA的机制，以及(Iii)了解这些酶的活性是如何整合到细胞代谢中的。利用酿酒酵母Rntlp酶作为真核细胞RNaseIII酶的模型，结合功能基因组学，研究该酶调控的新的基因表达途径。Rntlp在监测和调节编码铁摄取蛋白的mRNAs和参与蛋氨酸挽救途径的蛋白质中的功能将被研究。将开发新的基因组策略来识别受真核RNase III调控的其他基因表达途径。将通过定点突变和RNA底物的定点修饰来研究RNT1 p对双链RNA的识别和切割位点选择的机制。RNaseIII活性在细胞环境中的整合将被调查。特别是，我们将破译RNaseIII被招募到底物共转录的机制，以及RNaseIII在低铁条件下下调的机制。这些研究将有助于我们理解核糖核酸酶III在基因表达调控中的作用以及真核细胞代谢对铁缺乏的适应机制。

DESCRIPTION (provided by applicant): Post-transcriptional regulation has emerged as a potent way to control quantitatively and qualitatively gene expression. The RNase III family of double-stranded RNA endonucleases plays crucial functions in multiple gene expression pathways: they participate in the processing of precursors of ribosomal RNA, of small RNAs involved in splicing and rRNA metabolism, and of microRNAs. They also participate in the production of small interfering RNAs in the RNA interference process. Our long term goals are (i) to exhaustively identify the gene expression pathways controlled by eukaryotic members of the RNase III family of endonucleases, (ii) to understand the mechanisms by which these enzymes bind and cleave dsRNA and (iii) to understand how the activity of these enzymes is integrated in the cell metabolism. Using the S.cerevisiae enzyme Rntlp as a model eukaryotic RNase III enzyme and functional genomics, we will investigate novel gene expression pathways controlled by this enzyme. The functions of Rntlp in the surveillance and regulation of mRNAs encoding iron uptake proteins and for a protein involved in the methionine salvage pathway will be investigated. Novel genomic strategies will be developed to identify additional gene expression pathways regulated by eukaryotic RNases III. The recognition of double-stranded RNA and the mechanism of cleavage site selection by Rnt1 p will be studied using site directed mutagenesis and site-specific modifications of the RNA substrate. The integration of RNase III activity in the cellular context will be investigated. In particular, we will decipher the mechanism by which RNase III is recruited co-transcriptionally to its substrates, and the mechanism by which RNase III is down-regulated in low iron conditions. These studies will contribute to our understanding of the roles of RNase III in the control of gene expression and of the mechanisms of adaptation of eukaryotic cell metabolism to iron deficiency.