Organization and Evolution of the cotG and cotH Genes of Bacillus subtilis
Organization and Evolution of the cotG and cotH Genes of Bacillus subtilis
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DOI：
10.1128/jb.06121-11
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发表时间：
2011-12-01
影响因子：
3.2
通讯作者：
Baccigalupi, Loredana
中科院分区：
文献类型：
--
作者：
Giglio, Rosa;Fani, Renato;Baccigalupi, Loredana
枯草芽孢杆菌的cotG和cotH基因编码两种先前表征的孢子外壳蛋白。这两个基因在染色体上相邻，并由sigma（K）（RNA聚合酶的孢子形成特异性sigma因子）分歧地转录。我们报告的证据表明，cotH启动子映射812 bp上游的开始，其编码区和分歧cotG基因完全包含在启动子和编码部分的cotH。对所有完全测序的原核基因组的生物信息学分析表明，这种染色体组织在孢子形成杆菌中并不常见。事实上，CotG仅存在于B中。枯草芽孢杆菌（B. subtilis）、B.解淀粉菌和B. atrophaeus和两株土芽孢杆菌属菌株。当存在时，cotG总是编码由串联重复序列组成的模块化蛋白，并且总是接近但相对于cotH转录发散。生物信息学和基因组学数据表明，这样的基因组组织有一个共同的进化起源，现存的cotG基因的模块化结构是一个祖先的小基因的多轮基因延伸事件的结果。
The cotG and cotH genes of Bacillus subtilis encode two previously characterized spore coat proteins. The two genes are adjacent on the chromosome and divergently transcribed by sigma(K), a sporulation-specific sigma factor of the RNA polymerase. We report evidence that the cotH promoter maps 812 bp upstream of the beginning of its coding region and that the divergent cotG gene is entirely contained between the promoter and the coding part of cotH. A bioinformatic analysis of all entirely sequenced prokaryotic genomes showed that such chromosomal organization is not common in spore-forming bacilli. Indeed, CotG is present only in B. subtilis, B. amyloliquefaciens, and B. atrophaeus and in two Geobacillus strains. When present, cotG always encodes a modular protein composed of tandem repeats and is always close to but divergently transcribed with respect to cotH. Bioinformatic and phylogenic data suggest that such genomic organizations have a common evolutionary origin and that the modular structure of the extant cotG genes is the outcome of multiple rounds of gene elongation events of an ancestral minigene.