Danchin Antoine
Institut Pasteur, Docteur Roux, Paris Cedex 15, France.
Prog Mol Biol Transl Sci. 2009;85:1-41. doi: 10.1016/S0079-6603(08)00801-5.
A phylogenetic analysis of bacterial genomes shows them to comprise persistent genes, the "paleome" (Greek: palaios, ancient, reminiscent of the origin of life), associated with genes permitting development of life in a particular niche, the "cenome" (from koinos, common, a radical often used in ecology). Most ribonucleases belong to the former, demonstrating their central position in core life processes. These enzymes appear to have often (but not always) evolved through consistent scenarios, generally grouping bacteria into well-defined clades. The evolution of phosphorylases (which salvage energy) is particularly revealing, resulting in diverse complex structures whose function is to degrade RNA. The degradosome of the gamma-Proteobacteria is a paradigm of such complex structures that emphasizes the essential role of energy in degradative processes. The A+T-rich Firmicutes behave in a highly original manner, where many ribonucleases and related proteins coevolve as a group. The recent identification of novel activities in these organisms, stresses the (underestimated) importance of degradation of very short RNAs, as well as 5'-3' degradative processes in Bacteria.
对细菌基因组的系统发育分析表明，它们由持久性基因（“古基因组”，希腊语：palaios，意为古老，让人联想到生命起源）和允许在特定生态位中发展生命的基因（“共基因组”，源自koinos，意为共同，常用于生态学中的一个词根）组成。大多数核糖核酸酶属于前者，这表明它们在核心生命过程中的核心地位。这些酶似乎常常（但并非总是）通过一致的模式进化，通常将细菌分为明确的进化枝。磷酸化酶（用于挽救能量）的进化尤其具有启发性，产生了多种复杂结构，其功能是降解RNA。γ-变形菌的降解体就是这种复杂结构的一个范例，它强调了能量在降解过程中的重要作用。富含A+T的厚壁菌门表现出非常独特的行为方式，许多核糖核酸酶和相关蛋白作为一个群体共同进化。最近在这些生物体中发现的新活性，强调了极短RNA降解以及细菌中5'-3'降解过程（被低估）的重要性。
