DNA repair and the evolution of transformation in Bacillus subtilis. II. Role of inducible repair.
DNA repair and the evolution of transformation in Bacillus subtilis. II. Role of inducible repair.
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DNA 修复和枯草芽孢杆菌转化的进化。
DOI：
10.1093/genetics/121.3.411
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发表时间：
1989
期刊：
影响因子：
3.3
通讯作者：
Michod,RE
中科院分区：
文献类型：
--
作者：
Wojciechowski,MF;Hoelzer,MA;Michod,RE
在枯草芽孢杆菌中，DNA修复和重组与感受态密切相关，感受态是细菌可以结合、摄取和重组外源DNA的生理状态。以前，我们已经表明，同源DNA转化率（转化体与总细胞的比率）增加，如果细胞在暴露于UV辐射（UV-DNA）后转化，则随着UV剂量的增加而增加，而如果细胞在暴露于UV（DNA-UV）前转化，则转化率降低。在这份报告中，通过使用不同的DNA修复缺陷的突变体，我们表明，更大的增加转化率在UV-DNA实验比DNA-UV实验不依赖于切除修复或诱导型SOS样修复，虽然某些定量方面的反应依赖于这些修复系统。我们还表明，有没有增加的转化率在UV-DNA实验时，修复和重组熟练的细胞与非同源质粒DNA转化，虽然在DNA-UV实验的结果基本上是不变的，通过使用质粒DNA。我们已经使用DIN操纵子融合作为一种敏感的手段，测定在主管和非主管细胞亚群中的SOS样调节子控制下的基因表达，作为能力发展和我们随后的实验治疗的结果。结果表明，在我们的处理中，在主管和非主管亚群中诱导的SOS样系统，因此不应该是UV-DNA和DNA-UV处理中观察到的转化率差异反应的主要因素。这些结果进一步支持了这样的假设，即感受态的进化功能是将DNA带入细胞，作为DNA损伤修复的模板。
In Bacillus subtilis, DNA repair and recombination are intimately associated with competence, the physiological state in which the bacterium can bind, take up and recombine exogenous DNA. Previously, we have shown that the homologous DNA transformation rate (ratio of transformants to total cells) increases with increasing UV dosage if cells are transformed after exposure to UV radiation (UV-DNA), whereas the transformation rate decreases if cells are transformed before exposure to UV (DNA-UV). In this report, by using different DNA repair-deficient mutants, we show that the greater increase in transformation rate in UV-DNA experiments than in DNA-UV experiments does not depend upon excision repair or inducible SOS-like repair, although certain quantitative aspects of the response do depend upon these repair systems. We also show that there is no increase in the transformation rate in a UV-DNA experiment when repair and recombination proficient cells are transformed with nonhomologous plasmid DNA, although the results in a DNA-UV experiment are essentially unchanged by using plasmid DNA. We have used din operon fusions as a sensitive means of assaying for the expression of genes under the control of the SOS-like regulon in both competent and noncompetent cell subpopulations as a consequence of competence development and our subsequent experimental treatments. Results indicate that the SOS-like system is induced in both competent and noncompetent subpopulations in our treatments and so should not be a major factor in the differential response in transformation rate observed in UV-DNA and DNA-UV treatments. These results provide further support to the hypothesis that the evolutionary function of competence is to bring DNA into the cell for use as template in the repair of DNA damage.