ILLEGITIMATE RECOMBINATION IN PLANTS - A MODEL FOR T-DNA INTEGRATION
ILLEGITIMATE RECOMBINATION IN PLANTS - A MODEL FOR T-DNA INTEGRATION
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DOI：
10.1101/gad.5.2.287
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发表时间：
1991-02-01
影响因子：
10.5
通讯作者：
VANMONTAGU, M
中科院分区：
文献类型：
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作者：
GHEYSEN, G;VILLARROEL, R;VANMONTAGU, M
根癌农杆菌是一种土壤细菌，能够将DNA(T-DNA)转移到高等植物的基因组中，然后在那里稳定整合。从拟南芥中克隆了6个T-DNA插入片段及其相应的预插入位点，并对其进行了分析。分析包括两个来自烟草的T-DNA整合事件。T-DNA整合前后植物靶点的核苷酸序列比较表明，T-DNA通常只导致植物DNA中很小的(13-28个碱基)缺失，但可以发生更大的靶点重排。T-DNA末端和靶点之间的短同源性，以及连接处填充序列的存在，表明T-DNA整合是由非法重组介导的，植物中的这些过程与哺乳动物细胞中的情况非常相似。我们提出了一个基于有限碱基配对的T-DNA整合模型，用于初始突触，然后在连接处进行DNA修复。该模型的变化可以解释在DNA修复合成过程中通过聚合酶滑动和模板切换在连接处形成填充DNA，以及存在更大的植物靶DNA重排。
Agrobacterium tumefaciens is a soil bacterium capable of transferring DNA (the T-DNA) to the genome of higher plants, where it is then stably integrated. Six T-DNA inserts and their corresponding preinsertion sites were cloned from Arabidopsis thaliana and analyzed. Two T-DNA integration events from Nicotiana tabacum were included in the analysis. Nucleotide sequence comparison of plant target sites before and after T-DNA integration showed that the T-DNA usually causes only a small (13-28 bp) deletion in the plant DNA but larger target rearrangements can occur. Short homologies between the T-DNA ends and the target sites, as well as the presence of filler sequences at the junctions, indicate that T-DNA integration is mediated by illegitimate recombination and that these processes in plants are very analogous to events in mammalian cells. We propose a model for T-DNA integration on the basis of limited base-pairing for initial synapsis, followed by DNA repair at the junctions. Variations of the model can explain the formation of filler DNA at the junctions by polymerase slipping and template switching during DNA repair synthesis and the presence of larger plant target DNA rearrangements.