Natural chromosomal transformation (CT) plays a major role in prokaryote evolution, yet factors that govern the integration of DNA from related species remain poorly understood. We show that in naturally competent Bacillus subtilis cells the acquisition of homeologous sequences is governed by sequence divergence (SD). Integration initiates in a minimal efficient processing segment via homology‐directed CT, and its frequency decreases log‐linearly with increased SD up to 15%. Beyond this and up to 23% SD the interspecies boundaries prevail, the CT frequency marginally decreases, and short (<10‐nucleotides) segments are integrated via homology‐facilitated micro‐homologous integration. Both mechanisms are RecA dependent. We identify the other recombination proteins required for the acquisition of homeologous DNA. The absence of AddAB, RecF, RecO, RuvAB or RecU, crucial for repair‐by‐recombination, did not affect CT. However, dprA, radA, recJ, recX or recD2 inactivation strongly decreased intraspecies and interspecies CT. Interspecies CT was not detected beyond ~8% SD in ΔdprA, ~10% in ΔrecJ, ΔradA, ΔrecX and ~14% in ΔrecD2 cells. We propose that DprA, RecX, RadA/Sms, RecJ and RecD2 accessory proteins are important for the generation of genetic diversity. Together with RecA, they facilitate gene acquisition from bacteria of related species.

中文翻译：

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重组蛋白在枯草芽孢杆菌自然染色体转化过程中不同地控制同源DNA的获取

天然染色体转化（CT）在原核生物进化中起主要作用，但是，控制相关物种DNA整合的因素仍然知之甚少。我们表明在自然胜任的枯草芽孢杆菌中在细胞中，同源序列的获取受序列分歧（SD）支配。整合是通过同源定向CT在最小的有效处理段中启动的，其频率以对数线性下降，而SD增加到15％。除此之外，物种间界占优势，高达23％SD，CT频率略有下降，并且短片段（<10个核苷酸）通过同源性促进的微同源整合而整合。两种机制都依赖于RecA。我们确定获取同源DNA所需的其他重组蛋白。对于通过重组修复至关重要的AddAB，RecF，RecO，RuvAB或RecU的缺失不会影响CT。但是，dprA，radA，recJ，recX或recD2失活大大降低种内和种间CT。超出〜8％SD在Δ中没有检测种间CT DPRA，〜在Δ10％recJ，Δ RADA，Δ recX和〜14％的Δ recD2细胞。我们建议DprA，RecX，RadA / Sms，RecJ和RecD2辅助蛋白对于遗传多样性的产生很重要。它们与RecA一起可促进从相关物种的细菌中获取基因。