DNA Replication, Bacteria Cell Cycle, and Cell Growth

DNA 复制、细菌细胞周期和细胞生长

基本信息

批准号：
9214746
负责人：
Judith Zyskind
金额：
$ 33.6万
依托单位：
San Diego State University Foundation
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
1992
资助国家：
美国
起止时间：
1992-11-01 至 1996-04-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=9214746&HistoricalAwards=false
关键词：
DNA Replication Bacteria Cell Cycle

项目摘要

The goal of this project is to understand how initiation of DNA replication is coupled to growth rate. To understand how the frequency of the initiation event is determined, the mechanisms that regulate the expression of the DnaA protein must be understood. Both genetics and biochemistry are being used to elucidate the regulatory circuits controlling expression of the dnaA operon promoters. The growth rate regulator and alarmone, guanosine tetraphosphate (ppGpp), inhibits transcription from the dnaA P2 promoter. The molecular basis of this inhibition is being characterized in vitro. Mutants defective in the inhibitory response to ppGpp will be examined for growth rate regulation and precise timing of initiation of DNA replication in the cell cycle. We will determine whether the dnaA gene is still under growth rate control in cells that lack ppGpp - is there a growth rate regulation mechanism other than ppGpp that controls the expression of DnaA protein? We will investigate DnaA protein-DNA interactions by isolation and characterization of DnaA mutant proteins with altered DNA-binding specificities. We will construct a chromosomal mutation with genes on either side of oriC deleted, and the resulting mutant will be examined for loss of precise timing in the cell cycle. %%% This research studies the control of a key step in cell divison and should provide significant insights into a basic question in biology, as well as abberant conditions suchs as uncontrolled cell mutiplication.

该项目的目标是了解 DNA 复制的启动与生长速度之间的关系。为了了解起始事件的频率是如何确定的，必须了解调节 DnaA 蛋白表达的机制。遗传学和生物化学都被用来阐明控制 dnaA 操纵子启动子表达的调节电路。生长速率调节剂和警报酮、四磷酸鸟苷 (ppGpp) 抑制 dnaA P2 启动子的转录。这种抑制作用的分子基础正在体外进行表征。将检查对 ppGpp 抑制反应有缺陷的突变体的生长速率调节和细胞周期中 DNA 复制起始的精确时间。我们将确定在缺乏ppGpp的细胞中，dnaA基因是否仍处于生长速率控制之下——除了ppGpp之外，是否存在控制DnaA蛋白表达的生长速率调节机制？我们将通过分离和表征具有改变的 DNA 结合特异性的 DnaA 突变蛋白来研究 DnaA 蛋白-DNA 相互作用。我们将构建一个染色体突变，其中 oriC 两侧的基因被删除，并且将检查所产生的突变体是否丢失了细胞周期中的精确计时。 %%% 这项研究研究了细胞分裂关键步骤的控制，应该为生物学的基本问题以及不受控制的细胞增殖等异常条件提供重要的见解。