Lefèvre J C, Gasc A M, Burger A C, Mostachfi P, Sicard A M
Proc Natl Acad Sci U S A. 1984 Aug;81(16):5184-8. doi: 10.1073/pnas.81.16.5184.
In pneumococcal transformation, recombination frequency between point mutations is usually proportional to physical distances. We have identified an aberrant marker belonging to the amiA locus that appeared to markedly enhance recombination frequency when crossed with any other markers of this gene. This mutation results from the C-to-A transversion in the sequence A-T-T-C-A-T----A-T-T-A-A-T. This effect is especially apparent for short distances as small as 27 base pairs. The hyperrecombination does not require the wild-type function of the pneumococcal gene for an ATP-dependent DNase (which is homologous to the product of the Escherichia coli recBC genes) or of the hex genes, which correct certain mismatched bases in transformation. The hyperrecombination is affected by the presence of nearby mismatched bases that trigger an excision-repair system. It is proposed that the mutation that shows hyperrecombination is sometimes converted to the wild-type allele at the heteroduplex stage of transformation.
在肺炎球菌转化过程中，点突变之间的重组频率通常与物理距离成正比。我们鉴定出一个属于amiA位点的异常标记，当它与该基因的任何其他标记杂交时，似乎会显著提高重组频率。这种突变是由序列A-T-T-C-A-T----A-T-T-A-A-T中的C到A颠换引起的。对于短至27个碱基对的距离，这种效应尤为明显。这种超重组不需要肺炎球菌中依赖ATP的DNase基因（与大肠杆菌recBC基因的产物同源）或hex基因的野生型功能，hex基因在转化过程中可纠正某些错配碱基。超重组受到附近错配碱基的影响，这些错配碱基会触发切除修复系统。有人提出，表现出超重组的突变有时在转化的异源双链阶段会转换为野生型等位基因。
