mRNA的5’非翻译区(5’UTR)具有调控蛋白翻译效率和mRNA稳定性的重要功能。在马克斯克鲁维酵母中，3.2%的mRNA 5’UTR中存在长度超过8nt的多聚腺苷酸序列(poly(A))。前期研究发现5’UTR poly(A)参与调控了INU1, LAC4等基因的mRNA和蛋白水平，但机制不明。本项目拟以马克斯克鲁维酵母为模型，分析该酵母中所有5’UTR poly(A)(>8nt)对于mRNA和蛋白水平的影响。选择具有显著调控作用的poly(A)，测定它对于转录、mRNA稳定性、翻译效率和异质性的影响。在此基础上，鉴定poly(A)的长度和位置、以及poly(A)结合蛋白PABP对于poly(A)功能的影响；同时研究poly(A)的功能保守性和它在异源蛋白表达中的应用。本项目有望从基因组层次揭示5’UTR poly(A)调控表达的多重机制，并可能为合成生物学提供新的表达调控元件。

5’ untranslated region (5’UTR) of mRNA is implicated in regulating translational efficiency and stability of mRNA. In Kluyveromyces marxianus, 3.2% of mRNA 5’UTRs contain poly(A) (uninterrupted sequence of adenosine monophosphate) which is longer than 8nt. Preliminary studies showed that 5’UTR poly(A) of INU1 and LAC4 regulated levels of mRNA and proteins, but underlying mechanisms were unclear. This project will perform a genome-wide analysis of the roles of 5’UTR poly(A) (>8nt) in regulating mRNA and protein levels in Kluyveromyces marxianus. 5’UTR poly(A)s with significant regulatory functions will be chosen for further identifications. We will study the contributions of 5’UTR poly(A) to the transcription, mRNA stability, translational efficiency and heterogeneity of expression. The contributions of the length or position of poly(A), and that of the interactions between poly(A) and PABP, to the functions of 5’UTR poly(A), will be investigated. We will also study the functions of poly(A) in other yeast species, as well as the application of poly(A) in the expressions of heterologous proteins. This project will shed light on the multiple mechanisms by which 5’UTR poly(A) regulates gene expression in a genome-wide scale, but also provide novel biological parts for synthetic biology.