Langin T, Haedens V, Rossignol J L
Laboratoire Interactions Moléculaires Génomiques, Université Paris-Sud, Orsay, France.
Genetics. 1988 Jun;119(2):337-44. doi: 10.1093/genetics/119.2.337.
Large heterologies in gene b2 strongly increase the frequencies of reciprocal exchanges on their left border, towards the high conversion end. In a previous study, we observed that heterozygous point mutations located in the high conversion end (region F) stimulate the reciprocal exchanges instigated by the large heterology 138. We have defined some properties of this stimulation. The effect does not depend on the nature of the large heterology used. It is effective only with point mutations located on the left side of the large heterology. It does not depend on the number of heterozygosities accumulated in region F. It is not specific on the location of point mutations in region F: it decreases from region F (left end) to region E (middle part of b2). It is correlated with the mismatch correction efficiencies of the point mutations used. It is not observed in the absence of a large heterology. Point mutation heterozygosities which stimulate reciprocal exchanges also decrease the frequency of HDNA formation in gene b2. We propose a model in which reciprocal exchanges on the one hand and hybrid DNA formation on the other hand correspond to alternative processings of a common recombination intermediate.
基因b2中的大异源序列会显著增加其左边界朝向高转换端的相互交换频率。在先前的一项研究中，我们观察到位于高转换端（区域F）的杂合点突变会刺激由大异源序列138引发的相互交换。我们已经定义了这种刺激的一些特性。这种效应不取决于所使用的大异源序列的性质。它仅对位于大异源序列左侧的点突变有效。它不取决于区域F中积累的杂合性数量。它对区域F中点突变的位置不具有特异性：从区域F（左端）到区域E（b2的中部）它会降低。它与所使用的点突变的错配校正效率相关。在没有大异源序列的情况下未观察到这种现象。刺激相互交换的点突变杂合性也会降低基因b2中HDNA形成的频率。我们提出了一个模型，其中一方面相互交换，另一方面杂种DNA形成对应于共同重组中间体的替代加工过程。
