Efficient repair of DNA breaks in Drosophila: evidence for single-strand annealing and competition with other repair pathways.
Efficient repair of DNA breaks in Drosophila: evidence for single-strand annealing and competition with other repair pathways.
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果蝇 DNA 断裂的有效修复：单链退火和与其他修复途径竞争的证据。
DOI：
10.1093/genetics/161.2.711
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发表时间：
2002
期刊：
影响因子：
3.3
通讯作者：
Flores,Carlos
中科院分区：
文献类型：
--
作者：
Preston,ChristineR;Engels,William;Flores,Carlos
我们证明了在果蝇生殖系中诱导的DNA双链断裂可以通过单链退火（SSA）机制非常有效地修复。通过调动ap转座子，在1290-bp的直接重复序列的两个拷贝之间形成双链断裂。在获得该染色体的80%的后代中，正如在SSA中观察到的那样，修复导致了pelement的丢失和一个重复拷贝的丢失。这种修复的频率比使用等位基因模板的基因转换的频率要高得多，只有7%。一个类似的结构，但只有158 bp的重复，也产生了类似SSA的修复事件，但频率降低，并产生了一些修复途径以外的产物。1290-bp重复序列携带两个序列多态性，在产物中进行了检测。在假定的异双工中间，最靠近缺口的等位基因最常丢失。这种偏差是由SSA模型预测的，尽管其他模型可以解释它。我们得出结论，SSA是果蝇序列重复之间DNA断裂的首选修复途径，它与合成依赖性链退火（SDSA）途径的基因转换竞争。
We show evidence that DNA double-strand breaks induced in the Drosophila germ line can be repaired very efficiently by the single-strand annealing (SSA) mechanism. A double-strand break was made between two copies of a 1290-bp direct repeat by mobilizing aPtransposon. In >80% of the progeny that acquired this chromosome, repair resulted in loss of thePelement and loss of one copy of the repeat, as observed in SSA. The frequency of this repair was much greater than seen for gene conversion using an allelic template, which is only ∼7%. A similar structure, but with a smaller duplication of only 158 bp, also yielded SSA-like repair events, but at a reduced frequency, and gave rise to some products by repair pathways other than SSA. The 1290-bp repeats carried two sequence polymorphisms that were examined in the products. The allele nearest to a nick in the putative heteroduplex intermediate was lost most often. This bias is predicted by the SSA model, although other models could account for it. We conclude that SSA is the preferred repair pathway in Drosophila for DNA breaks between sequence repeats, and it competes with gene conversion by the synthesis-dependent strand annealing (SDSA) pathway.