MiR-968 And MiR-1002 Forming A MicroRNA Cluster Have Opposing Growth Regulation Functions

Due to the existence of various factors such as ionizing radiation,ultraviolet rays,genotoxic substances in the environment,and reactive oxygen species in the body,it triggers the damage of the organism's genomic DNA,activates the complex DNA damage response(DDR),and repairs damage DNA.Research on the basic mechanism of DDR has made tremendous progress,and many important protein regulators involved in DDR have been identified.Micro RNA(miRNA)is a type of non-coding RNA with a length of about 22 nucleotides.It functions by degrading target gene m RNA or inhibiting protein translation.It acts as an endogenous gene regulator and participates in DNA damage response.its function has been explained.These miRNAs involved in DDR can regulate the sensitivity of cells to DNA damage and have a certain impact on the occurrence and development of tumors.Therefore,it is necessary to further identify those miRNAs that can regulate DNA damage responses and explore their functions.This project uses Drosophila,a model organism,to study how miRNAs participate in DNA damage responses.Earlier results showed that miR-968-1002 KO flys are sensitive to radiation,showing S-phase checkpoint defects,an increase in apoptotic cells,and G2-M checkpoint defects after DNA damage,so this subject further studied their functions.First,establish the transgenic flies of miR-968 and miR-1002 respectively,and induce the expression of miR-968 and miR-1002 in the whole body or specific tissues of the flies.It was found that the induction of miR-968 in the wingdisc of the third stage larvae of Drosophila resulted in a significant reduction in tissue.And drosophila died in the pupal stage.It has also been found that miR-968 can significantly promote cell apoptosis.And further overexpress miR-968 at different developmental stages.However,miR-1002 was induced to express in the wing embryo tissue of the third stage larvae of Drosophila.The number of cells did not increase significantly but the tissues increased significantly.Its function is opposite to that of miR-968 in promoting apoptosis.Second,the analysis tools miRanda and Target Scan were used to analyze the potential target genes of miR-968 and miR-1002,respectively.The analysis focuses on target genes that have the function of regulating apoptosis and cell cycle.And the dual luciferase reporter gene system was used to verify the target genes in vitro culture system.It is found that miR-968 may target Abd-A and mts,and miR-1002 may target mts target genes.Results have shown that miR-968 may target the expanded gene of the Hippo signaling pathway.Therefore,this subject has further explored whether miR-968 participates in cell apoptosis by targeting the expanded genes of the Hippo signaling pathway in response to DNA damage.The results show that when the expanded expression is knocked down in the miR-968-1002 KO background,the apoptotic cells after DNA damage are slightly reduced compared with the miR-968-1002 KO drosophila strain.But compared with w1118 wild-type flies,it still increased.Therefore,the phenotype of miR-968-1002 KO flies after DNA damage may only partially depend on the Hippo signaling pathway.