Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, Missouri, USA.
Center for Women's Infectious Disease Research, Washington University School of Medicine, Saint Louis, Missouri, USA.
J Bacteriol. 2023 Apr 25;205(4):e0048722. doi: 10.1128/jb.00487-22. Epub 2023 Mar 6.
Initiation of DNA replication is required for cell viability and passage of genetic information to the next generation. Studies in Escherichia coli and Bacillus subtilis have established TPases ssociated with diverse cellular ctivities (AAA+) as essential proteins required for loading of the replicative helicase at replication origins. AAA+ ATPases DnaC in E. coli and DnaI in B. subtilis have long been considered the paradigm for helicase loading during replication in bacteria. Recently, it has become increasingly clear that most bacteria lack DnaC/DnaI homologs. Instead, most bacteria express a protein homologous to the newly described DciA ( ntecedent) protein. DciA is not an ATPase, and yet it serves as a helicase operator, providing a function analogous to that of DnaC and DnaI across diverse bacterial species. The recent discovery of DciA and of other alternative mechanisms of helicase loading in bacteria has changed our understanding of DNA replication initiation. In this review, we highlight recent discoveries, detailing what is currently known about the replicative helicase loading process across bacterial species, and we discuss the critical questions that remain to be investigated.
DNA 复制的起始是细胞存活和遗传信息传递到下一代所必需的。在大肠杆菌和枯草芽孢杆菌中的研究已经确定了与多种细胞活动相关的 TPases ssociated with diverse cellular ctivities（AAA+）是复制起始处复制解旋酶加载所必需的必需蛋白。大肠杆菌中的 DnaC 和枯草芽孢杆菌中的 DnaI 一直被认为是细菌复制过程中解旋酶加载的典范。最近，越来越明显的是，大多数细菌缺乏 DnaC/DnaI 同源物。相反，大多数细菌表达一种与新描述的 DciA（antecedent）蛋白同源的蛋白质。DciA 不是 ATP 酶，但它作为解旋酶的操作子，提供了与 DnaC 和 DnaI 在不同细菌物种中类似的功能。最近发现 DciA 以及细菌中其他替代的解旋酶加载机制改变了我们对 DNA 复制起始的理解。在这篇综述中，我们强调了最近的发现，详细介绍了目前在不同细菌物种中复制解旋酶加载过程的已知情况，并讨论了仍需研究的关键问题。
