Quiñones A, Kücherer C, Piechocki R, Messer W
Mol Gen Genet. 1987 Jan;206(1):95-100. doi: 10.1007/BF00326542.
We have analysed the transcription levels for the convergently overlapping Escherichia coli genes for the DNA polymerase III proofreading function (dnaQ) and ribonuclease H (rnh). The two tandem dnaQ promoters are about three times more active than the single rnh promoter as shown by analysing the level of in vivo transcription using dnaQ-galK and rnh-galK fusions. In E. coli mutants constitutively expressing the pleiotropic SOS response, which includes activities that enhance DNA repair, recombination and mutagenesis, a strong reduction in rnh transcription was observed. The lexA51 recA441 double mutant which fully expresses the SOS response shows the strongest reduction in rnh transcription and the highest increase in dnaQ transcription. Nuclease S1 mapping supported the finding that a constitutive expression of SOS function leads to a strong reduction in rnh transcription.
我们分析了大肠杆菌中DNA聚合酶III校对功能基因（dnaQ）和核糖核酸酶H基因（rnh）的反向重叠基因的转录水平。通过分析使用dnaQ-galK和rnh-galK融合体的体内转录水平，发现两个串联的dnaQ启动子的活性比单个rnh启动子大约高三倍。在组成型表达多效性SOS应答的大肠杆菌突变体中，观察到rnh转录显著减少，SOS应答包括增强DNA修复、重组和诱变的活性。完全表达SOS应答的lexA51 recA441双突变体显示rnh转录减少最为明显，而dnaQ转录增加最多。核酸酶S1图谱分析支持了SOS功能的组成型表达导致rnh转录显著减少这一发现。
