Frequent nonhomologous replacement of replicative helicase loaders by viruses in Vibrionaceae

• 成果类型: Article
• 署名作者: Tominaga, Kento; Ozaki, Shogo; Sato, Shohei; Katayama, Tsutomu; Nishimura, Yuki; Omae, Kimiho; Iwasaki, Wataru
• 署名单位: University of Tokyo; Kyushu University; University of Tokyo; University of Tokyo; University of Tokyo; University of Tokyo; University of Tokyo
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-11165
• DOI: 10.1073/pnas.2317954121
• 发表日期: 2024-05-07
• 关键词: dna-replication; gene set; protein; bacterial; Visualization; initiation; database

摘要

Several microbial genomes lack textbook - defined essential genes. If an essential gene is absent from a genome, then an evolutionarily independent gene of unknown function complements its function. Here, we identified frequent nonhomologous replacement of an essential component of DNA replication initiation, a replicative helicase loader gene, in Vibrionaceae . Our analysis of Vibrionaceae genomes revealed two genes with unknown function, named vdhL1 and vdhL2 , that were substantially enriched in genomes without the known helicase - loader genes. These genes showed no sequence similarities to genes with known function but encoded proteins structurally similar with a viral helicase loader. Analyses of genomic syntenies and coevolution with helicase genes suggested that vdhL1/2 encodes a helicase loader. The in vitro assay showed that Vibrio harveyi VdhL1 and Vibrio ezurae VdhL2 promote the helicase activity of DnaB. Furthermore, molecular phylogenetics suggested that vdhL1 / 2 were derived from phages and replaced an intrinsic helicase loader gene of Vibrionaceae over 20 times. This high replacement frequency implies the host's advantage in acquiring a viral helicase loader gene.