Okumura K, Kiyama R, Oishi M
Institute of Applied Microbiology, University of Tokyo, Japan.
Nucleic Acids Res. 1987 Sep 25;15(18):7477-89. doi: 10.1093/nar/15.18.7477.
Previously, we reported a recombination-prone human alphoid-like repetitive DNA (Sau3A family) which is characterized by abundance in the extrachromosomal fraction and restriction fragment length polymorphism. We suggested a specific homologous recombination to be responsible for the DNA excision from the chromosomes and also the sequence rearrangement in the chromosomes. In order to investigate the nature of the recombination further, 8 different clones were obtained which hybridized with Sau3A probe among over 1,500 extrachromosomal DNA clones. Restriction mapping and nucleotide sequence analyses showed two to be Sau3A monomers and dimers, four Sau3A recombinants, as observed previously, one a recombinant of the Sau3A-related sequence on chromosome 17, and one a new Sau3A-related sequence. Sequence analyses of the recombination junctions in the recombinant clones indicated a specific homologous recombination also to be responsible for all but one clone. The molecular mechanism and biological significance associated with the recombination are discussed.
此前，我们报道了一种易于重组的人类类α卫星重复DNA（Sau3A家族），其特征是在染色体外组分中含量丰富且存在限制性片段长度多态性。我们认为特定的同源重组是导致从染色体上切除DNA以及染色体上序列重排的原因。为了进一步研究重组的本质，在1500多个染色体外DNA克隆中获得了8个与Sau3A探针杂交的不同克隆。限制性图谱分析和核苷酸序列分析表明，其中两个是Sau3A单体和二聚体，四个是Sau3A重组体，如先前观察到的那样，一个是17号染色体上Sau3A相关序列的重组体，另一个是新的Sau3A相关序列。重组克隆中重组连接点的序列分析表明，除了一个克隆外，特定的同源重组也是其他所有克隆的原因。文中讨论了与重组相关的分子机制和生物学意义。
