权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Study on the Determination Mechanism of Flagellar Number in Bacterial Cell.

细菌细胞鞭毛数决定机制的研究。

基本信息

批准号：
03454001
负责人：
KUTSUKAKE Kazuhiro
金额：
$ 4.22万
依托单位：
HIROSHIMA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1992
项目状态：
已结题

项目摘要

During bacterial cell division cycle, various biosynthetic processes proceed under spatial and temporal controls and two daughter cells with the same structures are finally produced. Flagella can be considered as one of the most suitable systems to study genetic control of duplication of cellular constituents. Cytological study of Salmonella typhimurium indicated that the duplication of flagellar number occurs at the specific stage, the end of cell elongation period. However, it was found that, in the strains defective in the gene for anti-sigma factor specific for flagellar regulon, de novo synthesis of flagella occurs throughout cell elongation period. This result indicates that a negative feedback control exerted by the anti-sigma factor plays an important role in duplication process of flagellar number. As the cell elongates, the cell volume increases and the intracellular concentration of anti-sigma factor decreases, which allows the flagellar regulon expressed and results in initiation of de novo synthesis of flagella. The flhDC operon is known as an initiation operon of flagellar regulon. Transcriptional analysis of this operon revealed that its efficient expression is dependent on a nucleoid protein, H-NS. H-NS has been shown to modulate the supercoiling structure of bacterial chromosome. Because dynamic change of the topology of chromosome during DNA replication process can influence the association of H-NS with specific DNA regions, the expression of flagellar regulon and thus the synthesis of flagella may be regulated by DNA replication process through interaction of DNA with H-NS.

在细菌细胞分裂周期中，各种生物合成过程在时空控制下进行，最终产生两个结构相同的子细胞。鞭毛可以被认为是研究细胞组分复制的遗传控制的最合适的系统之一。鼠伤寒沙门氏菌的细胞学研究表明，鞭毛数目的复制发生在特定的时期，即细胞伸长期的末期。然而，发现在鞭毛调节子特异性抗σ因子基因缺陷的菌株中，鞭毛的从头合成发生在整个细胞伸长期。这一结果表明，负反馈控制施加的反西格玛因素在鞭毛数量的复制过程中起着重要的作用。随着细胞伸长，细胞体积增加，抗σ因子的细胞内浓度降低，这允许鞭毛调节子表达并导致鞭毛从头合成的起始。flhDC操纵子被称为鞭毛调节子的起始操纵子。该操纵子的转录分析表明，其有效表达依赖于一个类核蛋白，H-NS。已证明H-NS调节细菌染色体的超螺旋结构。由于DNA复制过程中染色体拓扑结构的动态变化可以影响H-NS与特定DNA区域的结合，因此DNA复制过程可能通过与H-NS的相互作用来调控鞭毛调节子的表达，从而调控鞭毛的合成。