Foster P L, Trimarchi J M, Maurer R A
Department of Environmental Health, Boston University School of Public Health, Boston University School of Medicine, Massachusetts 02118-2394, USA.
Genetics. 1996 Jan;142(1):25-37. doi: 10.1093/genetics/142.1.25.
Reversion of a lac- frameshift allele carried on an F' episome in Escherichia coli occurs at a high rate when the cells are placed under lactose selection. Unlike Lac+ mutations that arise during nonselective growth, the production of these adaptive mutations requires the RecA-RecBCD pathway for recombination. In this report, we show that enzymes that process recombination intermediates are involved in the mutagenic process. RuvAB and RecG, E. coli's two enzymes for translocating Holliday junctions, have opposite effects: RuvAB is required for RecA-dependent adaptive mutations, whereas RecG inhibits them.
当置于乳糖选择条件下时，携带于大肠杆菌F'附加体上的lac-移码等位基因会以高频率发生回复突变。与非选择性生长期间出现的Lac+突变不同，这些适应性突变的产生需要RecA-RecBCD重组途径。在本报告中，我们表明处理重组中间体的酶参与了诱变过程。大肠杆菌中用于移位霍利迪连接体的两种酶RuvAB和RecG具有相反的作用：RuvAB是RecA依赖性适应性突变所必需的，而RecG则抑制这些突变。
