Species-specific double-strand break repair and genome evolution in plants
Species-specific double-strand break repair and genome evolution in plants
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DOI：
10.1093/emboj/19.20.5562
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发表时间：
2000-10-16
期刊：
影响因子：
11.4
通讯作者：
Puchta, H
中科院分区：
文献类型：
--
作者：
Kirik, A;Salomon, S;Puchta, H
即使是关系密切的真核生物，在基因组大小上也可能有很大不同。虽然逆转录元件的插入是基因组扩增的一个主要来源，但调节物种特异性缺失的机制相当模糊。我们分析了拟南芥和烟草在双链断裂修复过程中缺失的形成，这两个双子叶植物的基因组大小相差20倍。DSB由罕见的切割限制性内切酶I-SCEI诱导，缺失通过含有I-SCEI位点的负选择标记基因的功能丧失来鉴定。虽然在两个物种中，微同源基因在连接形成中的部分使用是相似的，但在烟草中，40%的缺失伴随着插入。在拟南芥中没有检测到插入，因为更大的缺失发生得更频繁，这表明基因组大小和平均缺失长度之间可能存在负相关。这种相关性以前已经被一项关于相关昆虫基因组进化的理论研究所假设，我们的研究现在确定了这种现象的可能的分子原因，表明DSB修复的物种特异性差异确实可能影响基因组进化。
Even closely related eukaryotic species may differ drastically in genome size. While insertion of retroelements represents a major source of genome enlargement, the mechanism mediating species-specific deletions is fairly obscure. We analyzed the formation of deletions during double-strand break (DSB) repair in Arabidopsis thaliana and tobacco, two dicotyledonous plant species differing >20-fold in genome size. DSBs were induced by the rare cutting restriction endonuclease I-SceI and deletions were identified by loss of function of a negative selectable marker gene containing an I-SceI site. Whereas the partial-use of micro-homologies in junction formation was similar in both species, in tobacco 40% of the deletions were accompanied by insertions. No insertions could be detected in Arabidopsis, where larger deletions were more frequent, indicating a putative inverse correlation between genome size and the average length of deletions. Such a correlation has been postulated before by a theoretical study on the evolution of related insect genomes and our study now identifies a possible molecular cause for the phenomenon, indicating that species-specific differences in DSB repair might indeed influence genome evolution.