Moraxella catarrhalis Restriction-Modification Systems Are Associated with Phylogenetic Lineage and Disease
Moraxella catarrhalis Restriction-Modification Systems Are Associated with Phylogenetic Lineage and Disease
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DOI：
10.1093/gbe/evy226
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发表时间：
2018-11-01
影响因子：
3.3
通讯作者：
Seib, Kate L.
中科院分区：
文献类型：
--
作者：
Blakeway, Luke V.;Tan, Aimee;Seib, Kate L.
卡他莫拉菌是一种人类适应的病原体，是中耳炎(OM)和慢性阻塞性肺疾病恶化的主要原因。该物种包括两个主要的系统发育谱系，RB1和RB2/3。限制-修饰(R-M)系统是在其他细菌属中发现的为数不多的与谱系相关的基因之一，具有多种功能，包括防御外来入侵的DNA，维持物种形成，以及基因表达的表观遗传调节。在这里，我们定义了51个公开可用的卡他藻基因组中的R-M系统，并报告了它们在卡他藻系统发育谱系中的分布。观察到6个R-M系统与系统发育谱系(RB1或RB2/3)的关联，这可能通过限制DNA转化而促进谱系的进化。此外，我们观察到I型R-M系统和III型R-M系统之间的关系，在地理和临床上不同的卡他毛虫分离株中，I型R-M系统和III型R-M系统在单个基因座上保守。该基因座的III型R-M系统含有相变的III型DNA甲基转移酶modM，它控制着一个相变调节子(Phasevarion)。我们观察到modM的存在与OM相关的中耳分离株之间存在关联，表明modM介导的表观遗传调控在OM病理生物学中可能发挥作用。
Moraxella catarrhalis is a human-adapted pathogen, and a major cause of otitis media (OM) and exacerbations of chronic obstructive pulmonary disease. The species is comprised of two main phylogenetic lineages, RB1 and RB2/3. Restriction-modification (R-M) systems are among the few lineage-associated genes identified in other bacterial genera and have multiple functions including defense against foreign invadingDNA, maintenance of speciation, and epigenetic regulation of gene expression. Here, we define the repertoire of R-M systems in 51 publicly available M. catarrhalis genomes and report their distribution among M. catarrhalis phylogenetic lineages. An association with phylogenetic lineage (RB1 or RB2/3) was observed for six R-M systems, which may contribute to the evolution of the lineages by restricting DNA transformation. In addition, we observed a relationship between a mutually exclusive Type I R-M system and a Type III R-M system at a single locus conserved throughout a geographically and clinically diverse set of M. catarrhalis isolates. The Type III R-M system at this locus contains the phase-variable Type III DNA methyltransferase, modM, which controls a phasevarion (phase-variable regulon). We observed an association between modM presence and OM-associated middle ear isolates, indicating a potential role for ModM-mediated epigenetic regulation in OM pathobiology.