Snyder Lori A S, Butcher Sarah A, Saunders Nigel J
The Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK1.
Oxford University Bioinformatics Centre, The Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK2.
Microbiology (Reading). 2001 Aug;147(Pt 8):2321-2332. doi: 10.1099/00221287-147-8-2321.
Previously, a complete genome analysis of Neisseria meningitidis strain MC58 revealed the largest repertoire of putative phase-variable genes described in any species to date. Initial comparisons with two incomplete Neisseria spp. genome sequences available at that time revealed differences in the repeats associated with these genes in the form of polymorphisms, the absence of the potentially unstable elements in some alleles, and in the repertoire of the genes that were present. Analyses of the complete genomes of N. meningitidis strain Z2491 and Neisseria gonorrhoeae strain FA1090 have been performed and are combined with a comprehensive comparative analysis between the three available complete genome sequences. This has increased the sensitivity of these searches and provided additional contextual information that facilitates the interpretation of the functional consequences of repeat instability. This analysis identified: (i) 68 phase-variable gene candidates in N. meningitidis strain Z2491, rather than the 27 previously reported; (ii) 83 candidates in N. gonorrhoeae strain FA1090; and (iii) 82 candidates in N. meningitidis strain MC58, including an additional 19 identified through cross-comparisons with the other two strains. In addition to the 18 members of the opa gene family, a repertoire of 119 putative phase-variable genes is described, indicating a huge potential for diversification mediated by this mechanism of gene switching in these species that is central to their interactions with the host and environmental transitions. Eighty-two of these are either known (14) or strong (68) candidates for phase variation, which together with the opa genes make a total of 100 identified genes. The repertoires of the genes identified in this analysis diverge from the different species groupings, indicating horizontal exchange that significantly affects the species and strain complements of these genes.
此前，对脑膜炎奈瑟菌菌株MC58的全基因组分析揭示了迄今为止在任何物种中所描述的最大的假定相变基因库。最初与当时可用的两个不完整的奈瑟菌属基因组序列进行比较，发现与这些基因相关的重复序列存在多态性差异，一些等位基因中不存在潜在的不稳定元件，以及所存在基因的库也有所不同。对脑膜炎奈瑟菌菌株Z2491和淋病奈瑟菌菌株FA1090的全基因组进行了分析，并与三个可用的全基因组序列之间进行了全面的比较分析。这提高了这些搜索的灵敏度，并提供了额外的背景信息，有助于解释重复序列不稳定性的功能后果。该分析确定：（i）脑膜炎奈瑟菌菌株Z2491中有68个相变基因候选物，而非先前报道的27个；（ii）淋病奈瑟菌菌株FA1090中有83个候选物；（iii）脑膜炎奈瑟菌菌株MC58中有82个候选物，包括通过与其他两个菌株交叉比较鉴定出的另外19个。除了opa基因家族的18个成员外，还描述了119个假定的相变基因库，表明这种基因转换机制介导的多样化在这些物种中具有巨大潜力，这对于它们与宿主的相互作用和环境转变至关重要。其中82个是已知的（14个）或强烈（68个）的相变候选基因，它们与opa基因一起共有100个已鉴定基因。在该分析中鉴定出的基因库与不同的物种分组不同，表明水平交换显著影响了这些基因的物种和菌株组成。
