REGULATION OF METHIONINE METABOLISM IN BACILLUS SUBTILIS

枯草芽孢杆菌蛋氨酸代谢的调控

• 批准号: 6944586
• 负责人: TINA M. HENKIN
• 金额: $ 4.56万
• 依托单位: OHIO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-08-01 至 2006-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6944586
• 关键词: Bacillus subtilis; RNA binding protein; aminoacid metabolism; bacterial genetics; bacterial proteins; biochemistry; cell free system; genetic regulation; genetic terminator element; guanine nucleotides; intermolecular interaction; methionine; molecular genetics; nucleic acid sequence; nucleic acid structure; protein reconstitution; protein structure function; reporter genes; site directed mutagenesis; suppressor mutations; transcription factor; transcription termination

DESCRIPTION (provided by applicant): A novel global regulation system for control of genes involved in methionine metabolism has been uncovered in Bacillus subtilis. Genes utilizing this mechanism, designated the S box family, contain in their mRNA leader regions a complex set of conserved primary sequence and structural elements, including a transcriptional terminator, competing antiterminator, and anti-antiterminator. Genetic analyses indicate that during growth in methionine, sequences in the leader are required for stabilization of the anti-antiterminator, which prevents formation of the antiterminator, which in turn allows termination. The molecular mechanism for control of the leader RNA structure in response to methionine levels is unknown, although preliminary studies suggest that binding of a regulatory factor is required to prevent readthrough. This system is widely used for control of methionine-related genes in a variety of Gram-positive bacteria, including important pathogens such as Staphylococcus aureus, and is also found in the Gram-negative bacteria Chlorobium tepidum and Geobacter sulforreducens. Eleven transcriptional units are controlled by this mechanism in B. subtilis alone, so the total number of genes involved is high. The major goal of this study is to further investigate the molecular mechanism of transcription termination control, and to elucidate the physiological role of this system, using a combination of genetic and biochemical approaches. The required cis-acting sequence elements will be identified by site-directed mutagenesis. The trans-acting regulatory factors required for the methionine response will be identified, and the system will be examined both in vivo and in vitro. A requirement for ppGpp for efficient readthrough in vivo has been demonstrated, and the molecular basis for this requirement will be examined. Finally, the physiological role of genes of unknown function which appear to be regulated by this mechanism will be examined.

描述（由申请人提供）：一种新颖的全球监管体系 蛋氨酸代谢相关基因的控制已被发现 枯草芽孢杆菌。利用这种机制的基因被称为 S 盒家族， 在其 mRNA 前导区中包含一组复杂的保守初级 序列和结构元件，包括转录终止子， 竞争性反终结者和反反终结者。遗传分析表明 在蛋氨酸的生长过程中，前导序列中的序列是必需的 抗反终止子的稳定，防止形成 反终止子，反过来又允许终止。分子机制为 前导 RNA 结构响应蛋氨酸水平的控制是 未知，尽管初步研究表明监管的约束力 需要因子来防止通读。该系统广泛用于 控制多种革兰氏阳性菌中的蛋氨酸相关基因， 包括金黄色葡萄球菌等重要病原体，也发现 存在于革兰氏阴性细菌温热绿菌和硫还原地杆菌中。 枯草芽孢杆菌中有 11 个转录单位受此机制控制 单独的，因此涉及的基因总数很高。 本研究的主要目的是进一步探讨其分子机制 转录终止控制，并阐明其生理作用 该系统采用遗传和生化方法相结合的方法。这 所需的顺式作用序列元件将通过定点 诱变。蛋氨酸所需的反式作用调节因子 将确定反应，并对系统进行体内和体外检查 体外。体内有效通读 ppGpp 的要求是 已证实，并将检查这一要求的分子基础。 最后，功能未知的基因的生理作用似乎是 对此机制的监管将受到审查。