Abstract：
DNA double-strand breaks (DSBs) are the most severe DNA lesions and need to be removed immediately to prevent loss of genomic information. Recently, it has been revealed that DSBs induce novel transcription from the cleavage sites in various species, resulting in RNAs being referred to as damage-induced RNAs (diRNAs). While diRNA synthesis is an early event in the DNA damage response and plays an essential role in DSB repair activation, the location where diRNAs are newly generated in plants remains unclear, as does their transcriptional mechanism. Here, we performed the sequencing of polyadenylated (polyA) diRNAs that emerged around all DSB loci in Arabidopsis thaliana under the expression of the exogenous restriction enzyme Sbf I and observed 88 diRNAs transcribed via RNA polymerase II in 360 DSB loci. Most of the detected diRNAs originated within active genes and were transcribed from DSBs in a bidirectional manner. Furthermore, we found that diRNA elongation tends to terminate at the boundary of an endogenous gene located near DSB loci. Our results provide reliable evidence for understanding the importance of new transcription at DSBs and show that diRNA is a crucial factor for successful DSB repair.
摘要：
DNA双链断裂（DSB）是最严重的DNA损伤，需要立即去除以防止基因组信息丢失。最近,已经揭示了DSB从各种物种的切割位点诱导新的转录，导致RNA被称为损伤诱导的RNA(diRNA)。虽然diRNA合成是DNA损伤反应的早期事件，并且在DSB修复激活中起着至关重要的作用。diRNAs在植物中新产生的位置仍不清楚，它们的转录机制也是如此。这里,我们对在外源限制性内切酶SbfI表达下出现在拟南芥所有DSB基因座周围的聚腺苷酸化(polyA)diRNAs进行了测序,并在360个DSB基因座中观察到88个通过RNA聚合酶II转录的diRNAs.大多数检测到的diRNAs起源于活性基因，并以双向方式从DSB转录。此外，我们发现diRNA的延伸倾向于终止于位于DSB基因座附近的内源基因的边界。我们的结果为理解DSB新转录的重要性提供了可靠的证据，并表明diRNA是成功修复DSB的关键因素。
