Roles of protein phosphorylation, calcium ion and cytoskeltal proteins in bacterial cell cycle.

1.通过使用抗H-NS抗体在oriC-膜复合物中检测大肠杆菌组蛋白样蛋白H-NS。在DELTAhns突变株中观察到无核细胞产生和倍性降低。这些结果表明H-NS在染色体复制和分配机制中起重要作用.为了分析钙在大肠杆菌细胞周期中的作用，分离了生长受到抑制或依赖于高浓度钙的大肠杆菌突变体。分离携带CS2-29突变体中负责钙敏感性的基因的粘粒克隆，并在48分钟定位在染色体图谱上。类似地，分离携带负责SH 3450突变体中钙依赖性的基因的粘粒克隆，并在90分钟定位。为了分析cafA基因的功能，构建了cafA：：cat插入突变体。ams 1突变体的温度敏感性被cafA：：cat突变增强，并被cafA^+质粒部分抑制。在cafA：：cat突变体细胞中，积累了16 S rRNA和16.3S rRNA的前体。这些结果表明，cafA基因编码RNaseE样核糖核酸内切酶，其负责16 S rRNA成熟。

1. E.coli histone-like protein H-NS was detected in the oriC-membrane complex by using an anti-H-NS antibody. Anucleate cell production and decrease of ploidy were observed in the DELTAhns mutant strain. These results suggest that H-NS plays an important role in the mechanisms of chromosome replication and partitioning.2. E.coli mutants, in which the growth is inhibited or dependent on high concentrations of calcium, were isolated in order to analyze the role of calcium in E.coli cell cycle. A cosmid clone which carries the gene responsible for calcium sensitivity in CS2-29 mutant was isolated and mapped at 48 min on the chromosome map. Similarly, a cosmid clone which carries the gene responsible for calcium dependency in SH3450 mutant was isolated and mapped at 90 min.3. In order to analyze the function of the cafA gene, which forms cytoplasmic cytoskeltal structure, a cafA : : cat insertion mutant was constructed. Temperature sensitivity of the ams1 mutant was enhanced by the cafA : : cat mutation and was partially suppressed by cafA^+ plasmid. In the cafA : : cat mutant cells, precursors of 16S rRNA 16.3S rRNA were accumulated. These results indicate that the cafA gene encodes and RNaseE-like endoribonuclease which is responsible for 16S rRNA maturation.