Identification Of Mi Rnas In Response To DNA Damage In Fly And Preliminary Study On Their Apoptotic Function

DNA damage response is a mechanism by which the body can detect and repair damaged DNA,maintain the stability of the genome after recognizing DNA damage signals.DNA double-strand breaks are one of the most severe forms of DNA damage.Once ATM is recruited to the site of DNA damage,a series of downstream target proteins can be rapidly phosphorylated,causing cell cycle arrest,followed by DNA repair enzymes that repair the site of the injury.when DNA damage can not be repaired,the cells become apoptotic.Studies have shown that DNA damage and non-coding RNA are inextricably linked,Noncoding RNAs were once considered "evolutionary junk" because of their non-coding properties,however,there is growing evidence that it plays a huge role at the molecular level and that noncoding RNAs have become the current scientific research Hot spots.DNA damage can regulate miRNA expression at multiple levels,including transcription,post-transcriptional modification and degradation.For example,p53 can regulate the transcription of some miRNAs.What's more,mi RNAs are also involved in almost every part of the DNA damage response,including recognizing DNA damage,repairing damaged DNA,inducing cell cycle arrest and apoptosis.The defect of DNA damage response mechanism and the suppression of miRNA expression in the genome range are the hallmarks of many human cancers.Therefore,it is important to identify and screen the miRNA involved in the regulation of DNA damage response.Thus,we screened this part of the mi RNA in Drosophila organisms and studied its molecular mechanism.First,in view of the critical role of atm,p53 and e2f1 in DNA damage response,we screened 114 miRNAs differentially expressed under the DNA damage conditions in atm,p53,and e2f1 mutations.Sixty-three mutant miRNA strains were purchased,involving 63 miRNAs from RNA-seq.Through Viability assay and Mitotic chromosomes spreading,we screened 30 miRNA mutants susceptible or resistant to DNA damage.Next,we need to study its molecular mechanism,and our main focus is on apoptotic signaling pathways.Taking into account that once the DNA damaged,e2f1 and p53 can synergistically promote apoptosis,we analyzed the RNA-seq data and screened e2f1 and p53 independently regulated and co-regulated mi RNAs,a total of 83.These mi RNAs have the potential to synergistically modulate apoptosis.In addition,seven miRNA mutant strains were found to be apoptotic cells under the condition of DNA damage by caspase-3 staining,and miRNAs involved in these seven mutant strains could regulate apoptosis signaling pathway.These efforts not only provide a better understanding of the functional link between miRNAs and DNA damage response,but also provide new therapeutic options for many human diseases associated with defects in DNA damage response.