The diversity and evolution of cell cycle regulation in alpha-proteobacteria: a comparative genomic analysis
The diversity and evolution of cell cycle regulation in alpha-proteobacteria: a comparative genomic analysis
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DOI：
10.1186/1752-0509-4-52
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发表时间：
2010-04-28
影响因子：
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通讯作者：
Biondi, Emanuele G.
中科院分区：
文献类型：
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作者：
Brilli, Matteo;Fondi, Marco;Biondi, Emanuele G.
背景资料：在新月柄杆菌（Caulobacter crescentus）中，CtrA协调DNA复制、细胞分裂和极性形态发生，并被认为是细胞周期主调节因子。CtrA活性在细胞周期进程中变化，并通过磷酸化、蛋白水解和转录控制来调节。在磷酸化状态下，CtrA结合特定的DNA序列，调节参与细胞周期进程的基因的表达，并沉默复制起点。虽然电路调节CtrA是已知的在柄杆菌的分子细节，其保护和功能在其他α-proteobacteria仍然知之甚少。结果：直向同源的柄杆菌因子参与CtrA的调节系统地扫描在α-proteobacteria的基因组。特别地，在α-变形菌的代表性基因组中鉴定了divL-cckA-chpT-ctrA磷酸化中继、divJ-pleC-divK双组分系统、cpdR-rcdA-clpPX蛋白水解系统、甲基转移酶ccrM和转录调节因子dnaA和gcrA的正向表达基因。CtrA，DnaA和GcrA的结合位点和CcrM推定的甲基化位点预测在所有这些因素的启动子区域和功能控制的CtrA在所有alphas.Conclusions：调节细胞周期的架构被确定在所有代表性的α-proteobacteria，揭示了高度多样化的电路，但也是一个保守的逻辑功能。有人提出了一个进化模型，其中古代阿尔法已经拥有在柄杆菌中发现的所有模块，这些模块以各种连接排列。两个方案似乎演变：一个复杂的电路在柄杆菌目和根瘤菌目和一个简单的一个发现在Rhododocyanales。
Background: In the bacterium Caulobacter crescentus, CtrA coordinates DNA replication, cell division, and polar morphogenesis and is considered the cell cycle master regulator. CtrA activity varies during cell cycle progression and is modulated by phosphorylation, proteolysis and transcriptional control. In a phosphorylated state, CtrA binds specific DNA sequences, regulates the expression of genes involved in cell cycle progression and silences the origin of replication. Although the circuitry regulating CtrA is known in molecular detail in Caulobacter, its conservation and functionality in the other alpha-proteobacteria are still poorly understood.Results: Orthologs of Caulobacter factors involved in the regulation of CtrA were systematically scanned in genomes of alpha-proteobacteria. In particular, orthologous genes of the divL-cckA-chpT-ctrA phosphorelay, the divJ-pleC-divK two-component system, the cpdR-rcdA-clpPX proteolysis system, the methyltransferase ccrM and transcriptional regulators dnaA and gcrA were identified in representative genomes of alpha-proteobacteria. CtrA, DnaA and GcrA binding sites and CcrM putative methylation sites were predicted in promoter regions of all these factors and functions controlled by CtrA in all alphas were predicted.Conclusions: The regulatory cell cycle architecture was identified in all representative alpha-proteobacteria, revealing a high diversification of circuits but also a conservation of logical features. An evolutionary model was proposed where ancient alphas already possessed all modules found in Caulobacter arranged in a variety of connections. Two schemes appeared to evolve: a complex circuit in Caulobacterales and Rhizobiales and a simpler one found in Rhodobacterales.