Analysis of Deinococcus radiodurans's transcriptional response to ionizing radiation and desiccation reveals novel proteins that contribute to extreme radioresistance
Analysis of Deinococcus radiodurans's transcriptional response to ionizing radiation and desiccation reveals novel proteins that contribute to extreme radioresistance
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DOI：
10.1534/genetics.104.029249
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发表时间：
2004-09-01
期刊：
影响因子：
3.3
通讯作者：
Battista, JR
中科院分区：
文献类型：
--
作者：
Tanaka, M;Earl, AM;Battista, JR
在亚致死剂量电离辐射后的第一个小时内，72个基因在D.耐辐射菌R1。这些位点中的33个也是从干燥中恢复的R1培养物中表达的一组73个基因中的一个。对每种应激反应诱导最高的五种转录物是相同的，编码功能未知的蛋白质。与这些转录本对应的基因（ddrA、ddrB、ddrC、ddrD和pprA）被删除，无论是单独删除还是以所有可能的双向组合删除。突变株的表征定义了三个上位性组，反映了电离辐射引起的损伤的不同细胞反应。ddrA和ddrB基因产物具有互补的活性，并且使两个基因座失活产生的菌株比其中任一单个基因已缺失的菌株对电离辐射更敏感。这些蛋白质似乎介导与电离辐射抗性相关的高效RecA独立过程。pprA基因产物在自然转化过程中不是同源重组所必需的，但在从辐射损伤中恢复期间可能参与RecA依赖性过程。这些特征清楚地表明，新的机制显着有助于D的电离辐射抗性。耐辐射的
During the first hour after a sublethal dose of ionizing radiation, 72 genes were upregulated threefold or higher in D. radiodurans R1. Thirty-three of these loci were also among a set of 73 genes expressed in R1 cultures recovering from desiccation. The five transcripts most highly induced in response to each stress re the same and encode proteins of unknown function. The genes (ddrA, ddrB, ddrC, ddrD, and pprA) corresponding to these transcripts were deleted, both alone and in all possible two-way combinations. Characterization of the mutant strains defines three epistasis groups that reflect different cellular responses to ionizing radiation-induced damage. The ddrA and ddrB gene products have complementary activities and inactivating both loci generates a strain that is more sensitive to ionizing radiation than strains in which either single gene has been deleted. These proteins appear to mediate efficient RecA-independent processes connected to ionizing radiation resistance. The pprA gene product is not necessary for homologous recombination during natural transformation, but nevertheless may participate in a RecA-dependent process during recovery from radiation damage. These characterizations clearly demonstrate that novel mechanisms significantly contribute to the ionizing radiation resistance in D. radiodurans.