Non-homologous DNA end joining in plant cells is associated with deletions and filler DNA insertions
Non-homologous DNA end joining in plant cells is associated with deletions and filler DNA insertions
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DOI：
10.1093/nar/25.22.4650
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发表时间：
1997-11-15
影响因子：
14.9
通讯作者：
Levy, AA
中科院分区：
文献类型：
--
作者：
Gorbunova, V;Levy, AA
植物双链DNA断裂主要通过非同源末端连接修复，但这一过程的分子机制尚不清楚。我们研究了不同末端构型的线性化质粒DNA转化烟草细胞后的非同源末端连接，在新的末端连接处发现了多种序列，无序列改变的连接很少，在大多数情况下，在两个末端都发现缺失，并且通常在短重复序列处发生重新连接。植物连接的一个显著特征是存在相对较大的，长达1.2kb的插入物填充DNA来源于质粒的内部区域或烟草基因组DNA，一些插入片段具有由几个重组的质粒相关区域组成的复杂结构，这些数据表明，植物中双链断裂修复涉及广泛的末端降解，异位模板入侵后的DNA合成和多个模板开关，这种机制让人想起噬菌体T4中的合成依赖性重组，它也可以解释植物中与非法重组相关的频繁的“DNA混乱”。
Double strand DNA breaks in plants are primarily repaired via non-homologous end joining, However, little is known about the molecular events underlying this process, We have studied non-homologous end joining of linearized plasmid DNA with different termini configurations following transformation into tobacco cells, A variety of sequences were found at novel end junctions, Joining with no sequence alterations was rare, in most cases, deletions were found at both ends, and rejoining usually occurred at short repeats. A distinct feature of plant junctions was the presence of relatively large, up to 1.2 kb long, insertions (filler DNA), in similar to 30% of the analyzed clones, The filler DNA originated either from internal regions of the plasmid or from tobacco genomic DNA, Some insertions had a complex structure consisting of several reshuffled plasmid-related regions, These data suggest that double strand break repair in plants involves extensive end degradation, DNA synthesis following invasion of ectopic templates and multiple template switches, Such a mechanism is reminiscent of the synthesis-dependent recombination in bacteriophage T4, It can also explain the frequent 'DNA scrambling' associated with illegitimate recombination in plants.