Genetic composition of the Bacillus subtilis SOS system
Genetic composition of the Bacillus subtilis SOS system
复制标题
DOI：
10.1128/jb.187.22.7655-7666.2005
复制
发表时间：
2005-11-01
影响因子：
3.2
通讯作者：
Lovett, CM
中科院分区：
文献类型：
--
作者：
Au, N;Kuester-Schoeck, E;Lovett, CM
细菌的SOS反应包括对DNA损伤的全局转录反应。DNA损伤是由高度保守的重组蛋白RecA感知的，它促进了转录抑制因子LexA的失活。LexA的失活导致LexA调控基因的诱导（抑制），其中许多基因参与DNA损伤后的DNA修复和存活。为了鉴定枯草芽孢杆菌中潜在的reca -LexA调控基因，我们在所有带注释的开放阅读框的起始密码子上游300 bp范围内搜索了假定的LexA结合位点。我们发现62个基因可以被假定的LexA结合位点调控。通过迁移转移测定，我们发现LexA特异性结合到54个这些基因的调控区域的DNA上，这些基因被组织在34个假定的操作子中。通过DNA微阵列分析，我们发现33个具有LexA结合位点的基因在丝裂霉素C和紫外线辐射下均表现出reca依赖性诱导。在这33个SOS基因中，有22个不同的LexA结合位点在18个假定的操纵子之前。对不同的LexA结合位点进行比对，揭示了枯草芽孢杆菌操作符的扩展一致序列：5‘-CGAACATATGTTCG-3’。虽然枯草芽孢杆菌中RecA和LexA控制的基因数量与大肠杆菌相似，但在大肠杆菌中只有8个依赖RecA的SOS基因有同源对应物。
The SOS response in bacteria includes a global transcriptional response to DNA damage. DNA damage is sensed by the highly conserved recombination protein RecA, which facilitates inactivation of the transcriptional repressor LexA. Inactivation of LexA causes induction (derepression) of genes of the LexA regulon, many of which are involved in DNA repair and survival after DNA damage. To identify potential RecA-LexA-regulated genes in Bacillus subtilis, we searched the genome for putative LexA binding sites within 300 bp upstream of the start codons of all annotated open reading frames. We found 62 genes that could be regulated by putative LexA binding sites. Using mobility shift assays, we found that LexA binds specifically to DNA in the regulatory regions of 54 of these genes, which are organized in 34 putative operons. Using DNA microarray analyses, we found that 33 of the genes with LexA binding sites exhibit RecA-dependent induction by both mitomycin C and UV radiation. Among these 33 SOS genes, there are 22 distinct LexA binding sites preceding 18 putative operons. Alignment of the distinct LexA binding sites reveals an expanded consensus sequence for the B. subtilis operator: 5'-CGAACATATGTTCG-3'. Although the number of genes controlled by RecA and LexA in B. subtilis is similar to that of Escherichia coli, only eight B. subtilis RecA-dependent SOS genes have homologous counterparts in E. coli.