Strukturelle Basis der Polyadenylierung zytoplasmatischer Boten-RNA durch den GLD-2/GLD-3 Proteinkomplex

信使RNA的聚腺苷酸化是真核生物中一个必不可少的过程。在细胞核内，它影响着mRNA的稳定性和转运；在细胞质中，它影响着mRNA的翻译效率。细胞质中的多聚腺苷在多种细胞过程中是必不可少的。例如，母体来源的休眠细胞质mRNAs在卵母细胞成熟和早期发育的特定时间被激活，通过添加Poly(A)尾巴进行蛋白质合成。多聚(A)聚合酶(PAPs)是核苷酸转移酶家族的一种蛋白质，其催化核心区在物种间高度保守。与核内PAPs不同，细胞质PAPs被其他蛋白质激活，并与其他蛋白质共同作用。其功能的结构基础目前尚不清楚。我计划表征细胞质聚(A)聚合酶GLD-2/GLD-3复合体的X射线结构。这种复合体在进入减数分裂时使一组繁殖系的线虫mRNA化。我将使用结构信息来理解GLD-2/GLD-3是如何识别其底物mRNAs的，以及它是如何从典型的聚(A)聚合酶大家族中分离出来的。结构分析将允许在体外解剖GLD-2/GLD-3的功能，并在体内合作研究其性质和动力学。

Polyadenylation of messenger RNA is an essential process in eukaryotes. In the nucleus it influences mRNA stability and transport, while in the cytoplasm it impacts on mRNA translational efficiency. Cytoplasmic polyadenylation is essential for a variety of cellular processes. Dormant cytoplasmic mRNAs of maternal origin, for example, are activated for protein synthesis at specific times during oocyte maturation and early development by addition of a poly(A) tail. Polyadenylation is carried out by poly(A) polymerases (PAPs), proteins of the nucleotidyl-transferase family whose catalytic core domain is highly conserved across species. In contrast to nuclear PAPs, cytoplasmic PAPs are activated by and act in conjunction with other proteins. The structural basis for their function is currently unknown. I plan to characterize the X-ray structure of the cytoplasmic poly(A) polymerase GLD-2/GLD-3 complex. This complex polyadenylates a set of germline C.elegans mRNAs at the entry into meiosis. I will use the structural information to understand how GLD-2/GLD-3 recognizes its substrate mRNAs and how it has diverged from the large family of canonical poly(A) polymerases. The structural analysis will allow dissecting GLD-2/GLD-3 function in vitro, and, in collaboration, to study its properties and dynamics in vivo.