Expression Pattern And Functional Analysis Of Prmt7 In Medaka (Oryzias Latipes)

Protein arginine methylation is an important post-translational modification.The protein arginine methyltransferase 7(Prmt7)is a member of the protein arginine methyltransferase family(Prmts),which catalyzes the methylation of arginine residues of the substrate to monomethylarginine(MMA).Prmt7 participate in a variety of life events through the regulation of gene expression,cell signal transduction and other processes.In this paper we studied the expression pattern of prmt7 gene in medaka and its function during embryonic development.The main results obtained are as follows:1.The length of the open reading frame of the prmt7 gene is 2085bp,which encoding 695 amino acids.The gene contains 17 exons and 16 introns.Domain prediction analysis revealed that Prmt7 contains two S-adenosyl-L-methionine binding domains(SAM-MT1 and SAM-MT2)and a core PrmA motif unique to the PRMTs family.Through amino acid multiple sequence alignment,phylogenetic tree analysis and collinearity analysis,it was found that the protein is very conservative in evolution.2.The results of RT-PCR and Real-Time PCR showed that the Prmt7 transcripts existed in the maternal stage during embryonic development.The expression level of Prmt7 transcripts was higher in the 8 cell stage and morula stage,but decreased from the blastocyst stage.Low-level expression continues until emergence.WISH results showed that the expression of prmt7 gene was higher in the brain and ear vesicles of medaka embryos.RT-PCR analysis showed that prmt7 gene expressed in all tissues of medaka,but has the highest expression in the ovary.In situ hybridization showed that the prmt7 gene was strongly expressed in stage Ⅰ-Ⅳ oocytes in the ovary of adult medaka,and weak expression signals could also be detected in follicular cells.The prmt7 gene is mainly expressed in sperm cells and spermatozoa in the testis of adults.These results suggest that Prmt7 may play a role in embryonic development and germ cell development.3.The function of prmt7 gene in the embryonic development of the medaka was studied using overexpression and knockdown strategies.The results showed that the overexpression of prmt7 gene had no significant effect on embryonic development of the medaka.Microinjection of prmt7 MO,which reduces the expression of the prmt7 gene,could delay the outsourcing process of medaka embryos.The whole mount in situ hybridization was used to detect primordial germ cells.It was found that knockdown of prmt7 did not change the number of primordial germ cells significantly,but affect the migration of primordial germ cells.The results showed that Prmt7 may play a role in the migration of the primordial germ cells of the medaka.This result has yet to be further verified.4.Adults and embryos of medaka were treated with hypoxia.Real-time PCR was used to detect the expression of prmt7 gene.It was found that he expression of prmt7 gene was significantly increased both in the tissues of adult medaka and in early stage embryos of medaka after hypoxia treatment.This indicated that prmt7 was a hypoxic response gene.5.Injecting LPS into the abdomen of the medaka,it was found that the expression of prmt7 in the spleen of the medaka significantly increased on the second day after the immune stimulation,and the expression of prmt7 in the kidney increased significantly on the third day after the immune stimulation;the expression of prmt7 increased significantly on the fourth day after immune stimulation.The poly I:C injection was performed in the abdomen of the medaka,and it was found that the expression level of prmt7 in the spleen and intestine of the medaka significantly increased on the second day after the immune stimulation;the expression of prmt7 in the kidney increased significantly on the third day;and the expression of prmt7 in liver increased significantly on the fourth day.These results indicated that Prmt7 may participate in the immune response of the medaka...