Alonso J C, Stiege A C, Lüder G
Max-Planck-Institut für molekulare Genetik, Berlin, Germany.
Mol Gen Genet. 1993 May;239(1-2):129-36. doi: 10.1007/BF00281611.
A recN- (recN1) strain of Bacillus subtilis was constructed. The effects of this and recF, recH and addAB mutations on recombination proficiency were tested. Mutations in the recN, recF, recH and addAB genes, when present in an otherwise Rec+ B. subtilis strain, did not affect genetic exchange. Strains carrying different combinations of mutations in these genes were constructed and examined for their sensitivity to 4-nitroquinoline-1-oxide (4NQO) and recombination proficiency. The recH mutation did not affect the 4NQO sensitivity of recN and recF cells and it only marginally affected that of addA addB cells. However, it reduced genetic recombination in these cells 10(2)- to 10(4)-fold. The addA addB mutations increased the 4NQO sensitivity of recF and recN cells, but completely blocked genetic recombination of recF cells and marginally affected recombination in recN cells. The recN mutation did not affect the recombinational capacity of recF cells. These data indicate that the recN gene product is required for DNA repair and recombination and that the recF, recH and addAB genes provide overlapping activities that compensate for the effects of single mutants proficiency. We proposed that the recF, recH, recB and addA gene products define four different epistatic groups.
构建了枯草芽孢杆菌的recN -（recN1）菌株。测试了该菌株以及recF、recH和addAB突变对重组能力的影响。当recN、recF、recH和addAB基因的突变存在于其他方面为Rec⁺的枯草芽孢杆菌菌株中时，并不影响基因交换。构建了携带这些基因不同突变组合的菌株，并检测它们对4 - 硝基喹啉 - 1 - 氧化物（4NQO）的敏感性和重组能力。recH突变不影响recN和recF细胞对4NQO的敏感性，对addA addB细胞的敏感性影响也很小。然而，它使这些细胞中的基因重组减少了10²至10⁴倍。addA addB突变增加了recF和recN细胞对4NQO的敏感性，但完全阻断了recF细胞的基因重组，对recN细胞的重组影响很小。recN突变不影响recF细胞的重组能力。这些数据表明recN基因产物是DNA修复和重组所必需的，并且recF、recH和addAB基因提供了重叠的活性，以补偿单个突变体能力的影响。我们提出recF、recH、recB和addA基因产物定义了四个不同的上位性组。
