Kakeda M, Ueguchi C, Yamada H, Mizuno T
Laboratory of Molecular Microbiology, School of Agriculture, Nagoya University, Japan.
Mol Gen Genet. 1995 Sep 20;248(5):629-34. doi: 10.1007/BF02423459.
From Escherichia coli, a DNA-binding protein that preferentially recognizes a curved DNA sequence was isolated and shown to correspond to one that has recently been reported as a binding protein for the replication origin of the E. coli chromosome, named Rob. Here, a rob promoter-lacZ transcriptional fusion was constructed on the chromosome, and used to demonstrate that the expression of rob is notably enhanced at the onset of stationary phase in Luria-broth and also under certain growth conditions in a minimal medium, such as glucose- and phosphate-starvation medium. It was further shown that this growth condition-dependent expression of rob is notably reduced in a null mutant for the stationary phase-specific sigma subunit of RNA polymerase, sigma s, although sigma s-independent expression of rob was significant during the logarithmic growth phase. Furthermore the rob null mutant was found to exhibit, as compared with the wild-type, an altered profile of protein synthesis, particularly at the very late stationary phase.
从大肠杆菌中分离出一种优先识别弯曲DNA序列的DNA结合蛋白，结果表明它与最近报道的一种大肠杆菌染色体复制起点的结合蛋白相对应，该蛋白名为Rob。在此，构建了一个染色体上的rob启动子-lacZ转录融合体，用于证明rob的表达在Luria肉汤的稳定期开始时显著增强，并且在基本培养基的某些生长条件下，如葡萄糖和磷酸盐饥饿培养基中也会增强。进一步表明，rob的这种生长条件依赖性表达在RNA聚合酶的稳定期特异性σ亚基σs的缺失突变体中显著降低，尽管在对数生长期rob的σs非依赖性表达很显著。此外，发现与野生型相比，rob缺失突变体表现出蛋白质合成谱的改变，特别是在稳定期末期。
