Mechanism of selenoprotein synthesis in Archaea

硒代半胱氨酸在新生蛋白质中的共翻译插入是通过在生命的所有三个领域中从无意义到有意义地重新编码专用的UGA密码子进行的。密码子意义的程序性改变涉及硒蛋白mRNA上的二级结构SECIS元件，但其结构、定位以及与之相互作用的因素在细菌、真核生物和古细菌中有所不同。虽然在细菌和真核生物中已经很好地描述了secis依赖性的UGA编码，但对古细菌中各自的机制知之甚少。本课题旨在确定与古细菌SECIS元件特异性结合的因子，研究这些因子及其在体外和体内与SECIS元件的相互作用，以揭示硒代半胱氨酸抑制SECIS依赖性UGA的古细菌机制。

Co-translational insertion of selenocysteine into nascent proteins proceeds by recoding dedicated UGA codons, from non-sense to sense, in all three domains of life. This programmed alteration of codon meaning involves a secondary structure on the selenoprotein mRNA, the SECIS element, but its structure, localization, and the factors interacting with it differ in Bacteria, Eukarya and Archaea. While SECIS-dependent recoding of UGA is well characterized in Bacteria and Eukarya, little is known about the respective mechanism in Archaea. To identify factors specifically binding to archaeal SECIS elements, to characterize these factors and their interaction with SECIS elements in vitro and in vivo, in order to unravel the archaeal mechanism of SECIS-dependent UGA suppression with selenocysteine, is the aim of the proposed project.