REGULATION OF BACILLUS SUBTILIS TRNA SYNTHETASE GENES

描述（改编自研究者摘要）：枯草芽孢杆菌 tyrS基因是一组氨酰-tRNA合成酶和氨基酸的成员 生物合成基因，命名为T盒家族，其由一个 独特的转录抗终止系统。 这些基因的表达是 依赖于转录物的前导区与 特异性不带电荷的tRNA 这种相互作用促进了 抗终止子结构，防止转录的过早终止。 至少有27个基因已被确定为该家族的成员， 革兰氏阳性菌，包括几种致病菌。 T盒 在革兰氏阴性菌中尚未发现其作用机制。 tyrS基因 是这个群体中最具特色的成员。 的特异性 前导RNA-tRNA相互作用依赖于 tRNA在前导序列中有一个单一的密码子，即“指定序列”， 将tRNA的受体末端与tRNA的一部分配对， 抗终止剂 这些配对是成功互动的必要条件， 但tRNA和前导序列的其他特征可能也很重要。 本研究的一个目标是进一步研究这种相互作用，使用 基因和生物化学技术。 一些保守的前导序列 区域元件对于抗终止是必不可少的。 第二个主要目标是 研究这些元素的分子作用。 而tRNA的前导基因 抗终止需要相互作用，但尚不清楚这是否 互动就足够了。 本研究的第三个主要目标是确定 通过突变分析和通过 在体外和异源细胞中重建抗终止系统 主持人 总的来说，这些研究旨在阐明 T盒基因抗终止机制。

DESCRIPTION (adapted from investigator's abstract): The Bacillus subtilis tyrS gene is a member of a group of aminoacyl-tRNA synthetase and amino acid biosynthesis genes, designated the T box family, which are regulated by a unique transcription antitermination system. Expression of these genes is dependent on interaction of the leader region of the transcript with a specific uncharged tRNA. This interaction promotes formation of an antiterminator structure, preventing premature termination of transcription. At least 27 genes have been identified as members of this family in Gram-positive bacteria, including several pathogenic species. The T box mechanism has not yet been found in Gram negative bacteria. The tyrS gene is the best characterized member of this group. The specificity of the leader RNA-tRNA interaction is dependent on pairing of the anticodon of the tRNA with a single codon, the "specifier sequence," in the leader, and on pairing of the acceptor end of the tRNA with a portion of the antiterminator. These pairings are necessary for a successful interaction, but other features of the tRNA and the leader are likely to be important. One goal of this study is to further investigate this interaction, using both genetic and biochemical techniques. A number of conserved leader region elements are essential for antitermination. A second major goal is examination of the molecular role of these elements. While the tRNA-leader interaction is required for antitermination, it is not clear that this interaction is sufficient. A third major goal of this study is to identify any additional required factors by mutational analyses, and by reconstitution of the antitermination system in vitro and in a heterologous host. Overall these studies are designed to elucidate the molecular mechanism of T box gene antitermination.