Functional analysis of the sbcD (dr1921) gene of the extremely radioresistant bacterium Deinococcus radiodurans  

作　　者：HU YiHuai MA ChenYu TIAN Bing LIN Jun HUA YueJin 

机构地区：[1]Key Laboratory of Chinese Ministry of Agriculture for Nuclear-Agricultural Sciences, Institute of Nuclear-Agricultural Sciences Zhejiang University, Hangzhou 310029, China [2]College of Life Sciences, Zhejiang University, Hangzhou 310029, China [3]College of Life Sciences and Chemical Engineering, Huaiyin Institute of Technology, Huai'an 223001, China

出　　处：《Chinese Science Bulletin》2007年第18期2506-2513,共8页

基　　金：Supported by the National Basic Research Program of China (Grant No. 2004CB19604);National Science Fund for Distinguished Young Scholars (Grant No. 30425038);Key Project from the National Natural Science Foundation of China (Grant No. 30330020)

摘　　要：In eukaryotes, the Mre11-Rad50-Nbs1 (MRN) complex, which resides at the crossroads of DNA repair and checkpoint signaling, rapidly forms prominent foci at damage sites following double-strand break (DSB) induction. This complex carries out the initial processing of the DSB ends. Mutations in the genes that encode components of this complex result in DNA-damage hypersensitivity, genomic in- stability, telomere shortening, and aberrant meiosis. Therefore, the MR proteins are highly conserved during evolution. The bacterial orthologs of Mre11 and Rad50 are the SbcD and SbcC proteins, respec- tively. Deinococcus radiodurans, an extremely radioresistant bacterium, is able to mend hundreds of radiation-induced DSBs. The SbcD and SbcC proteins were identified as the products of the Dr1921 and Dr1922 genes. Disruption of the sbcD gene, by direct reverse-orientation insertional mutagenesis tech- nology, remarkably increases the cells’ sensitivity to various types of DNA damaging agents, such as ionizing radiation, ultraviolet irradiation, hydrogen peroxide, and mitomycin C. We also provide evidence that the drSbcD protein plays an important role in both growth and DNA repair in this organ- ism, especially in repair of DSBs generated after cellular exposure to 6000 Gy of IR. These results demonstrate that the drSbcD protein plays an important role in DSBs repair in D. radiodurans.In eukaryotes, the Mre11-Rad50-Nbs1 （MRN） complex, which resides at the crossroads of DNA repair and checkpoint signaling, rapidly forms prominent foci at damage sites following double-strand break （DSB） induction. This complex carries out the initial processing of the DSB ends. Mutations in the genes that encode components of this complex result in DNA-damage hypersensitivity, genomic instability, telomere shortening, and aberrant meiosis. Therefore, the MR proteins are highly conserved during evolution. The bacterial orthologs of Mre11 and Rad50 are the SbcD and SbcC proteins, respectively. Deinococcus radiodurans, an extremely radioresistant bacterium, is able tO mend hundreds of radiation-induced DSBs. The SbcD and SbcC proteins were identified as the products of the Dr1921 and Dr1922 genes. Disruption of the sbcD gene, by direct reverse-orientation insertional mutagenesis technology, remarkably increases the cells＇ sensitivity to various types of DNA damaging agents, such as ionizing radiation, ultraviolet irradiation, hydrogen peroxide, and mitomycin C. We also provide evidence that the drSbcD protein plays an important role in both growth and DNA repair in this organism, especially in repair of DSBs generated after cellular exposure to 6000 Gy of IR. These results demonstrate that the drSbcD protein plays an important role in DSBs repair in Do radiodurans.

关 键 词：辐射阻抗细菌 基因分析 泛函分析 DNA修补 

分 类 号：Q78[生物学—分子生物学]