Retrohoming of a bacterial group II intron: Mobility via complete reverse splicing, independent of homologous DNA recombination
Retrohoming of a bacterial group II intron: Mobility via complete reverse splicing, independent of homologous DNA recombination
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DOI：
10.1016/s0092-8674(00)81586-x
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发表时间：
1998-08-21
期刊：
影响因子：
64.5
通讯作者：
Belfort, M
中科院分区：
文献类型：
--
作者：
Cousineau, B;Smith, D;Belfort, M
乳酸乳球菌可移动的第二组内含子，LI.LtrB，为分析遗传易感细菌系统中的归巢途径提供了机会。在这里，我们证明了LI.LtrB在大肠杆菌和乳酸杆菌中都是通过基于RNA的后归巢机制发生的。令人惊讶的是，后归巢在缺乏RecA功能的情况下发生得很有效，对侧翼外显子同源性的要求很宽松，也没有外显子标记的共转换。这些结果导致了一个细菌后归巢模型，在该模型中，内含子通过完全反向剪接整合到受体DNA中，并作为DNA合成的模板。返巢反应是通过DNA修复事件以前所未有的方式完成的，该事件独立于等位基因之间的同源重组。因此，LI.LtrB具有许多反转录转座子的特征，具有实用和进化意义。
The mobile group II intron of Lactococcus lactis, LI.LtrB, provides the opportunity to analyze the homing pathway in genetically tractable bacterial systems. Here, we show that LI.LtrB mobility occurs by an RNA-based retrohoming mechanism in both Escherichia coli and L. lactis. Surprisingly, retrohoming occurs efficiently in the absence of RecA function, with a relaxed requirement for flanking exon homology and without coconversion of exon markers. These results lead to a model for bacterial retrohoming in which the intron integrates into recipient DNA by complete reverse splicing and serves as the template for cDNA synthesis. The retrohoming reaction is completed in unprecedented fashion by a DNA repair event that is independent of homologous recombination between the alleles. Thus, LI.LtrB has many features of retrotransposons, with practical and evolutionary implications.