Comparative genomics of Streptococcus thermophilus phage species supports a modular evolution theory
Comparative genomics of Streptococcus thermophilus phage species supports a modular evolution theory
复制标题
DOI：
10.1128/jvi.73.10.8647-8656.1999
复制
发表时间：
1999-10-01
影响因子：
5.4
通讯作者：
Brüssow, H
中科院分区：
文献类型：
--
作者：
Lucchini, S;Desiere, F;Brüssow, H
五个完全测序的嗜热链球菌噬菌体基因组的比较分析表明，它们的多样化是通过DNA重组事件和点突变的积累相结合来实现的。这五个站点包括来自三个不同地理区域的溶解性和温带站点，包括PAC站点和COS站点。遗传交换的单位要么是大的，包括整个形态发生基因簇，不包括假定的尾纤维基因，或小的，由一个或最多两个基因，甚至基因片段。许多插入缺失的侧翼是DNA重复序列。单个推定尾纤维基因的差异与噬菌体的宿主范围相关。预测的尾丝蛋白由高度保守的结构域组成，该结构域含有明显的甘氨酸重复序列，其中穿插有高度可变的结构域。在T-偶联大肠杆菌噬菌体粘附素中，含甘氨酸的结构域是重组热点。在一个高度保守的。DNA复制区，所有裂解酶显示一个短的重复，在三个分离物的复制起点重复。可以想象的是，溶原性病毒可以通过溶原性模块中的缺失和多重重排事件从温带病毒中衍生出来，从而产生偶尔的自私病毒，这些自私病毒无视相应温带病毒的超感染控制系统。
The comparative analysis of five completely sequenced Streptococcus thermophilus bacteriophage genomes demonstrated that their diversification was achieved by a combination of DNA recombination events and an accumulation of point mutations. The five phages included lytic and temperate phages, both pac site and cos site, from three distinct geographical areas. The units of genetic exchange were either large, comprising the entire morphogenesis gene cluster, excluding the putative tail fiber genes, or small, consisting of one or maximally two genes or even segments of a gene. Many indels were flanked by DNA repeats. Differences in a single putative tail fiber gene correlated with the host ranges of the phages. The predicted tail fiber protein consisted of highly conserved domains containing conspicuous glycine repeats interspersed with highly variable domains. As in the T-even coliphage adhesins, the glycine-containing domains were recombinational hot spots. Downstream of a highly conserved. DNA replication region, all lytic phages showed a short duplication; in three isolates the origin of replication was repeated. The lytic phages could conceivably be derived from the temperate phages by deletion and multiple rearrangement events in the lysogeny module, giving rise to occasional selfish phages that defy the superinfection control systems of the corresponding temperate phages.