Matic I, Radman M, Rayssiguier C
Laboratoire de Mutagénèse, Institut Jacques Monod, Paris, France.
Genetics. 1994 Jan;136(1):17-26. doi: 10.1093/genetics/136.1.17.
To get more insight into the control of homologous recombination between diverged DNA by the Mut proteins of the long-patch mismatch repair system, we have studied interspecies Escherichia coli/Salmonella typhimurium recombination. Knowing that the same recombination pathway (RecABCD) is responsible for intraspecies and interspecies recombination, we have now studied the structure (replacement vs. addition-type or other rearrangement-type recombinants) of 81 interspecies recombinants obtained in conjugational crosses between E. coli donor and mutL, mutS, mutH, mutU or mut+ S. typhimurium recipients. Taking advantage of high interspecies sequence divergence, a physical analysis was performed on one third of the E. coli Hfr genome, which was expected to be transferred to S. typhimurium F- recipients during 40 min before interruption of the mating. Probes specific for each species were hybridized on dot blots of genomic DNA, or on colonies, and the composition of the rrn operons was determined from purified genomic DNA. With very few exceptions, the structure of these interspecies recombinants corresponds to replacements of one continuous block of the recipient genome by the corresponding region of the donor genome.
为了更深入地了解长片段错配修复系统的Mut蛋白对分歧DNA之间同源重组的控制，我们研究了种间大肠杆菌/鼠伤寒沙门氏菌的重组。由于已知种内和种间重组由相同的重组途径（RecABCD）负责，我们现在研究了在大肠杆菌供体与mutL、mutS、mutH、mutU或mut+鼠伤寒沙门氏菌受体之间的接合杂交中获得的81个种间重组体的结构（替代型与添加型或其他重排型重组体）。利用种间高度的序列差异，对三分之一的大肠杆菌高频重组基因组进行了物理分析，预计在交配中断前的40分钟内，该基因组会转移到鼠伤寒沙门氏菌F-受体中。针对每个物种的探针与基因组DNA的斑点印迹或菌落杂交，并从纯化的基因组DNA中确定rrn操纵子的组成。除了极少数例外，这些种间重组体的结构对应于受体基因组的一个连续片段被供体基因组的相应区域所替代。
