A recA null mutation may be generated in Streptomyces coelicolor
A recA null mutation may be generated in Streptomyces coelicolor
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DOI：
10.1128/jb.00951-06
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发表时间：
2006-10-01
影响因子：
3.2
通讯作者：
Chen, Carton W.
中科院分区：
文献类型：
--
作者：
Huang, Tzu-Wen;Chen, Carton W.
重组酶RecA在细菌的同源重组和SOS反应中起着至关重要的作用。虽然recA突变体通常在同源重组中有缺陷并且生长不良，但是它们可以在几乎所有细菌中分离。在此之前，几个实验室在链霉菌中产生recA无效突变时遇到了相当大的困难，并且分离出的唯一recA无效突变体（来自变铅青链霉菌）似乎伴随着抑制突变。利用大肠埃希菌-链霉菌接合介导的基因置换，我们在一系列天蓝色链霉菌A3（2）菌株中产生了recA无效突变。这些recA突变体对丝裂霉素C非常敏感，但对UV照射仅中度敏感，UV存活曲线显示宽肩，反映了recA独立修复途径的存在。在生长过程中，突变体分离出活力低的微小菌落，并产生比野生型更多的无核孢子。recA无效突变体对之间的一些杂交没有产生可检测的重组体，首次表明S. coelicolor是recA介导的，但其他突变体保留了进行重组的能力。这种新的重组活性的性质是未知的。
The recombinase RecA plays a crucial role in homologous recombination and the SOS response in bacteria. Although recA mutants usually are defective in homologous recombination and grow poorly, they nevertheless can be isolated in almost all bacteria. Previously, considerable difficulties were experienced by several laboratories in generating recA null mutations in Streptomyces, and the only recA null mutants isolated (from Streptomyces lividans) appeared to be accompanied by a suppressing mutation. Using gene replacement mediated by Eschetichia coli-Streptomyces conjugation, we generated recA null mutations in a series of Streptomyces coelicolor A3(2) strains. These recA mutants were very sensitive to mitomycin C but only moderately sensitive to UV irradiation, and the UV survival curves showed wide shoulders, reflecting the presence of a recA-independent repair pathway. The mutants segregated minute colonies with low viability during growth and produced more anucleate spores than the wild type. Some crosses between pairs of recA null mutants generated no detectable recombinants, showing for the first time that conjugal recombination in S. coelicolor is recA mediated, but other mutants retained the ability to undergo recombination. The nature of this novel recombination activity is unknown.