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MOLECULAR GENETICS OF BACILLUS SUBTILIS CYTOCHROME AA3

枯草芽孢杆菌细胞色素 AA3 的分子遗传学

基本信息

批准号：
3303715
负责人：
HARRY W TABER
金额：
$ 9.91万
依托单位：
NYSDOH/HEALTH RESEARCH, INC.
依托单位国家：
美国
项目类别：
财政年份：
1991
资助国家：
美国
起止时间：
1991-07-06 至 1994-06-30
项目状态：
已结题

项目摘要

Cytochrome aa3 is a multi-subunit enzyme complex that functions as a terminal oxidase in the respiratory chains of prokaryotic and eukaryotic cells. Although cytochrome aa3 has been well-studied biochemically, its genetic regulation is poorly understood. A number of hereditary human myopathies and encephalomyopathies have been traced to genes regulating formation of the mature complex. Molecular studies of cytochrome aa3 regulation are facilitated in bacteria because of its biochemical simplicity in these organisms. In addition, some bacteria contain variants of cytochrome aa3, for example caa3 or ba3, which because of unique characteristics can offer new insights into mechanism and regulation of the cytochrome aa3 family. This project addresses the regulation of cytochrome caa3 formation in Bacillus subtilis. The system has several attributes that make it particularly suitable: i) B. subtilis endospore formation is presently being described in molecular terms, ii) proper regulation of the respiratory chain is known to be critical to initiation of sporulation, iii) classical and molecular genetic technologies are well-developed; iv) B. subtilis is the only organism thus far shown to possess both cytochromes aa3 and caa3. Of particular importance are several regulatory genes identified in B. subtilis that affect cytochrome aa3 and caa3 formation. The structural genes for B. subtilis cytochrome caa3 (the ctaBCDEF cluster) recently have been cloned and sequenced. Physical, genetic, and transcriptional analyses are to be made of this cluster. Approaches will include integrational disruption, low- and high-resolution transcript mapping, and formation of gene fusions, a particular focus will be on the ctaA and strC gene products as possible transcriptional factors. The strC gene will be cloned for further study. Possibilities for participation of the ctaA and ctaB gene products in post-transcriptional regulation of cytochrome caa3 will be tested by immunochemical measurement of its subunits in ctaA and ctaB mutant backgrounds. The sca and scs suppressors of ctaA are to be studied genetically to gain insight into the functioning of these genes in the regulatory network that encompasses regulation of cytochrome aa3 and cytochrome caa3, as well as early events in the sporulation process.

细胞色素 aa3 是一种多亚基酶复合物，其功能为原核和真核生物呼吸链中的末端氧化酶细胞。尽管细胞色素 aa3 已在生化方面得到了充分研究，但它人们对基因调控知之甚少。人类有许多遗传肌病和脑肌病可追溯到调节基因成熟复合体的形成。细胞色素 aa3 的分子研究由于其生化特性，细菌中的调节得到促进这些生物体的简单性。此外，一些细菌还含有变异体细胞色素 aa3，例如 caa3 或 ba3，由于其独特的特征可以为机制和监管提供新的见解细胞色素 aa3 家族。该项目致力于细胞色素的调节枯草芽孢杆菌中 caa3 的形成。系统有几个属性这使得它特别适合： i) 枯草芽孢杆菌内生孢子的形成是目前正在用分子术语进行描述，ii）适当调节已知呼吸链对于孢子形成的启动至关重要， iii) 经典和分子遗传技术十分发达；四）枯草芽孢杆菌是迄今为止唯一被证明拥有两种细胞色素的生物体 aa3 和 caa3。特别重要的是几个调控基因在枯草芽孢杆菌中鉴定出影响细胞色素 aa3 和 caa3 形成的。枯草芽孢杆菌细胞色素 caa3 的结构基因（ctaBCDEF 簇）最近已被克隆并测序。身体、遗传和将对这个簇进行转录分析。方法将包括整合破坏、低分辨率和高分辨率转录本作图和基因融合的形成，特别关注的是 ctaA 和 strC 基因产物作为可能的转录因子。 strC 基因将被克隆以供进一步研究。参与的可能性 ctaA 和 ctaB 基因产物在转录后调控中的作用细胞色素 caa3 将通过免疫化学测量其 ctaA 和 ctaB 突变体背景中的亚基。 sca 和 scs 抑制器 ctaA 的基因将被研究以深入了解其功能这些基因在调控网络中的作用细胞色素 aa3 和细胞色素 caa3，以及早期事件孢子形成过程。