Brézellec Pierre, Petit Marie-Agnès, Pasek Sophie, Vallet-Gely Isabelle, Possoz Christophe, Ferat Jean-Luc
Universite de Versailles Saint-Quentin en Yvelines UFR des Sciences, France.
Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France.
Genome Biol Evol. 2017 Jun 1;9(6):1561-1566. doi: 10.1093/gbe/evx111.
At the onset of the initiation of chromosome replication, bacterial replicative helicases are recruited and loaded on the DnaA-oriC nucleoprotein platform, assisted by proteins like DnaC/DnaI or DciA. Two orders of bacteria appear, however, to lack either of these factors, raising the question of the essentiality of these factors in bacteria. Through a phylogenomic approach, we identified a pair of genes that could have substituted for dciA. The two domesticated genes are specific of the dnaC/dnaI- and dciA-lacking organisms and apparently domesticated from lambdoid phage genes. They derive from λO and λP and were renamed dopC and dopE, respectively. DopE is expected to bring the replicative helicase to the bacterial origin of replication, while DopC might assist DopE in this function. The confirmation of the implication of DopCE in the handling of the replicative helicase at the onset of replication in these organisms would generalize to all bacteria and therefore to all living organisms the need for specific factors dedicated to this function.
在染色体复制起始时，细菌复制性解旋酶在DnaC/DnaI或DciA等蛋白质的协助下被招募并加载到DnaA - oriC核蛋白平台上。然而，有两类细菌似乎缺乏这些因子中的任何一种，这就引发了这些因子在细菌中是否必不可少的问题。通过系统发育基因组学方法，我们鉴定出一对可能替代dciA的基因。这两个驯化基因是缺乏dnaC/dnaI和dciA的生物体所特有的，显然是从λ样噬菌体基因驯化而来。它们分别源自λO和λP，分别被重新命名为dopC和dopE。预计DopE会将复制性解旋酶带到细菌复制起点，而DopC可能在该功能中协助DopE。这些生物体中DopCE在复制起始时对复制性解旋酶处理过程中的作用得到证实，将使所有细菌乃至所有生物体都普遍需要专门负责此功能的特定因子。
