Hua Xiaoting, Huang Lifen, Tian Bing, Hua Yuejin
Key Laboratory of Chinese Ministry of Agriculture for Nuclear-Agricultural Sciences, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Kaixuan RD 268, Hangzhou, Zhejiang 310029, China.
Mutat Res. 2008 May 10;641(1-2):48-53. doi: 10.1016/j.mrfmmm.2008.02.003. Epub 2008 Feb 13.
Deinococcus radiodurans is a bacterium which can survive extremely DNA damage. To investigate the relationship between recQ and the ultraviolet radiation (UV) damage repair pathway, we created a four mutant strain by constructing recQ knockout mutants in uvrA1, uvrA2, and uvsE backgrounds. Using the rpoB/Rif(r) system, we measured the mutation frequencies and rates in wild type, recQ (MQ), uvsE uvrA1 uvrA2 (TNK006), and uvsE uvrA1 uvrA2 recQ (TQ). We then isolated Rif(r) mutants of these strains and sequenced the rpoB gene. The mutation frequency of TQ was 6.4, 10.1, and 2.43 times that of wild type, MQ, and TNK006, respectively, and resulted in rates of 4.7, 6.71, and 2.15 folds higher than that of wild type, MQ, and TNK006, respectively. All the strains demonstrated specific mutational hotspots. Furthermore, the TQ strain showed a transversion bias that was different from the other three strains. The results indicate that recQ is involved in the ultraviolet damage repair pathway via the interaction between recQ and uvrA1, uvrA2, and uvsE in D. radiodurans.
耐辐射球菌是一种能够在极端DNA损伤条件下存活的细菌。为了研究recQ与紫外线（UV）损伤修复途径之间的关系，我们通过在uvrA1、uvrA2和uvsE背景下构建recQ基因敲除突变体，创建了一个四重突变菌株。利用rpoB/Rif(r)系统，我们测量了野生型、recQ（MQ）、uvsE uvrA1 uvrA2（TNK006）和uvsE uvrA1 uvrA2 recQ（TQ）的突变频率和速率。然后我们分离了这些菌株的Rif(r)突变体，并对rpoB基因进行了测序。TQ的突变频率分别是野生型、MQ和TNK006的6.4倍、10.1倍和2.43倍，其突变率分别比野生型、MQ和TNK006高4.7倍、6.71倍和2.15倍。所有菌株都表现出特定的突变热点。此外，TQ菌株表现出一种与其他三个菌株不同的颠换偏向。结果表明，在耐辐射球菌中，recQ通过recQ与uvrA1、uvrA2和uvsE之间的相互作用参与紫外线损伤修复途径。
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