Mechanism of selenoprotein synthesis in Archaea

在生命的所有三个领域，通过重新编码特定的UGA密码子，从无义到有义，将硒半胱氨酸共翻译插入新生蛋白质中。这种程序性密码子意义的改变涉及到硒蛋白mRNA上的二级结构，SECIS元件，但它的结构、定位和与其相互作用的因素在细菌、真核生物和古生菌中是不同的。虽然细菌和真核生物对UGA的编码依赖于SECIS，但对古生菌中各自的机制知之甚少。确定与古生菌SECIS元件特异结合的因子，表征这些因子及其在体内外与SECIS元件的相互作用，以揭示硒半胱氨酸抑制SECIS依赖的UGA的古生菌机制，是本项目的目标。

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.