The processive kinetics of gene conversion in bacteria.
The processive kinetics of gene conversion in bacteria.
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DOI：
10.1111/mmi.13661
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发表时间：
2017-06
影响因子：
3.6
通讯作者：
Hughes D
中科院分区：
文献类型：
--
作者：
Paulsson J;El Karoui M;Lindell M;Hughes D
基因转换，即从一个同源序列到另一个同源序列的非互惠转移，是进化动力学中的主要力量，促进基因家族的共同进化，并保持重复基因之间的相似性。然而，这种转移的性质——从哪里开始，进行到什么程度，以及错配修复如何影响最终的转换链——还没有得到很好的理解。在这里，我们使用沙门氏菌中重复的tuf基因作为基因转换的定量可处理的模型系统。我们选择在tuf的多个不同位置进行转换，并检查了错配修复缺陷和错配修复熟练菌株中转换束的分布。考虑转换基本步骤的简单随机模型显示，使用相同的转换过程值（该模型的唯一动力学参数）与所有选择点的数据非常吻合。分析表明，基因转换在tuf基因内的任何位置有效地均匀地开始，并且在受基因边界限制的任何方向上都有有效的均匀转换过程。
Gene conversion, non‐reciprocal transfer from one homologous sequence to another, is a major force in evolutionary dynamics, promoting co‐evolution in gene families and maintaining similarities between repeated genes. However, the properties of the transfer – where it initiates, how far it proceeds and how the resulting conversion tracts are affected by mismatch repair – are not well understood. Here, we use the duplicate tuf genes in Salmonella as a quantitatively tractable model system for gene conversion. We selected for conversion in multiple different positions of tuf, and examined the resulting distributions of conversion tracts in mismatch repair‐deficient and mismatch repair‐proficient strains. A simple stochastic model accounting for the essential steps of conversion showed excellent agreement with the data for all selection points using the same value of the conversion processivity, which is the only kinetic parameter of the model. The analysis suggests that gene conversion effectively initiates uniformly at any position within a tuf gene, and proceeds with an effectively uniform conversion processivity in either direction limited by the bounds of the gene.