Increased frequency of homologous recombination and T-DNA integration in Arabidopsis CAF-1 mutants
Increased frequency of homologous recombination and T-DNA integration in Arabidopsis CAF-1 mutants
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DOI：
10.1038/sj.emboj.7601434
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发表时间：
2006-11-29
期刊：
影响因子：
11.4
通讯作者：
Toki, Seiichi
中科院分区：
文献类型：
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作者：
Endo, Masaki;Ishikawa, Yuichi;Toki, Seiichi
染色质组装因子1（CAF-1）参与DNA复制后的核小体组装和核苷酸切除修复。在拟南芥中，三个CAF-1亚基分别由FAS 1、FAS 2和最可能的MSI 1编码。在这项研究中，我们问是否基因组稳定性改变fas 1和fas 2突变体缺乏CAF-1活性。任何一个亚基的缺失都使植物体细胞同源重组（HR）的频率增加了40倍。转移DNA（T-DNA）整合的频率也升高。将组蛋白加载到新复制或修复的DNA上的延迟可能会使这些DNA片段更容易被修复酶和外源DNA所接近。此外，Fas突变体表现出增加的DNA双链断裂水平，G2期阻滞，加速核内复制，和升高的水平的mRNA编码的蛋白质参与HR-所有的因素，也可能有助于上调的HR频率在Fas突变体。
Chromatin assembly factor 1 (CAF-1) is involved in nucleo some assembly following DNA replication and nucleotide excision repair. In Arabidopsis thaliana, the three CAF-1 subunits are encoded by FAS1, FAS2 and, most likely, MSI1, respectively. In this study, we asked whether genomic stability is altered in fas1 and fas2 mutants that are lacking CAF-1 activity. Depletion of either subunit increased the frequency of somatic homologous recombination (HR) in planta similar to 40-fold. The frequency of transferred DNA (T-DNA) integration was also elevated. A delay in loading histones onto newly replicated or repaired DNA might make these DNA stretches more accessible, both to repair enzymes and to foreign DNA. Furthermore, fas mutants exhibited increased levels of DNA double-strand breaks, a G2-phase retardation that accelerates endoreduplication, and elevated levels of mRNAs coding for proteins involved in HR-all factors that could also contribute to upregulation of HR frequency in fas mutants.