Masuda Y, Ohtsubo E
Institute of Molecular and Cellular Biosciences, University of Tokyo, Japan.
J Bacteriol. 1994 Sep;176(18):5861-3. doi: 10.1128/jb.176.18.5861-5863.1994.
The chpB locus is a chromosomal homolog of the pem locus, which is responsible for stable maintenance of plasmid R100 within the host cells. Like pem, chpB codes for two genes, chpBK and chpBI, encoding a growth inhibitor and a suppressor for the killing action of the ChpBK protein, respectively. Here, we determined the precise location of the chpB locus, which is linked to ileR and ppa in the order ileR-chpB-ppa, at 95.7 min on the map of Escherichia coli. We then constructed mutants with an insertion of a (cat) fragment within chpBK or chpBI on the E. coli chromosome. These mutants grew normally, indicating that chpB is dispensable for cell growth.
chpB基因座是pem基因座的染色体同源物，pem基因座负责质粒R100在宿主细胞内的稳定维持。与pem一样，chpB编码两个基因，chpBK和chpBI，分别编码一种生长抑制剂和ChpBK蛋白杀伤作用的抑制剂。在这里，我们确定了chpB基因座的精确位置，它与ileR和ppa相连，顺序为ileR-chpB-ppa，位于大肠杆菌图谱的95.7分钟处。然后，我们构建了在大肠杆菌染色体上chpBK或chpBI内插入一个（cat）片段的突变体。这些突变体生长正常，表明chpB对细胞生长是可有可无的。
