Little or no repair of cyclobutyl pyrimidine dimers is observed in the organellar genomes of the young Arabidopsis seedling
Little or no repair of cyclobutyl pyrimidine dimers is observed in the organellar genomes of the young Arabidopsis seedling
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DOI：
10.1104/pp.111.1.19
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发表时间：
1996-05-01
期刊：
影响因子：
7.4
通讯作者：
Britt, AB
中科院分区：
文献类型：
--
作者：
Chen, JJ;Jiang, CZ;Britt, AB
紫外线（UV）诱导的环丁基嘧啶二聚体（CPD）的Southern-blot为基础的，位点特异性测定，采用CPD特异性酶T4内切酶V，被用来跟踪这种损伤的修复，特别是在5至6天的拟南芥幼苗的DNA序列。CPDs，作为酶敏感位点，在核序列中被迅速删除的光，但修复缓慢，如果在所有，在黑暗中。这一结果与先前对总细胞DNA中CPD的分析结果相同。在相同的DNA制剂中的代表性叶绿体和线粒体序列的测定显示，与核序列相反，酶敏感位点在可见光的存在和不存在下都被无效地消除。这些观察结果表明，拟南芥幼苗具有很少或根本没有能力的细胞器基因组中的CPD的修复。鉴于事实上，紫外线剂量的使用只有轻微影响幼苗的生长，我们认为，拟南芥幼苗必须具有非常有效的机制（S）的耐受紫外线诱导的DNA损伤。
A Southern-blot-based, site-specific assay for ultraviolet (UV)induced cyclobutyl pyrimidine dimers (CPDs), employing the CPD-specific enzyme T4 endonuclease V, was used to follow the repair of this lesion in particular DNA sequences in 5- to 6-d-old Arabidopsis thaliana seedlings. CPDs, measured as enzyme-sensitive sites, in nuclear sequences were removed rapidly in the light but were repaired slowly, if at all, in the dark. This result was identical to that obtained in prior analyses of CPDs in total cellular DNA. Assay of representative chloroplast and mitochondrial sequences in the same DNA preparations revealed that, in contrast to nuclear sequences, enzyme-sensitive sites are inefficiently eliminated in both the presence and absence of visible light. These observations suggest that Arabidopsis seedlings possess little or no capacity for the repair of CPDs in the organellar genomes. Given the fact that the UV dose employed only marginally affected the growth of the seedlings, we suggest that Arabidopsis seedlings must possess very efficient mechanism(s) for the tolerance of UV-induced DNA damage.