Effect of ezrin regulation by sperm-borne miR-183 on the formation of microvilli and early development of bovine embryos
Background: Mature sperm contain both coding and non-coding RNAs, which can be delivered into an oocyte with the sperm at fertilization. Accumulating evidence shows that these sperm-borne RNAs play crucial roles in epigenetic reprogramming, remodeling, embryonic development, and offspring phenotype. MiR-183 is highly expressed in bovine sperm, and can be delivered into oocytes during fertilization. Results: Here we used bioinformatics and luciferase assays to show that the ezrin gene, EZR, is
... rin gene, EZR, is one of the targets of miR-183 in early embryos, while gain- and loss-of-function studies demonstrated their regulatory relationship. Scanning electron microscopy showed that the density of microvilli on the surface of somatic cell nuclear transfer (SCNT) embryos was significantly higher than on in vitro fertilized (IVF) embryos and was significantly reduced by injection of miR-183. EZR-siRNA injected into SCNT embryos had a similar effect. This indicated that a deficiency in sperm-borne miRNA-183 might lead to abnormal changes in microvilli by down-regulating ezrin protein. We used bioinformatics to select the proteins that worked in combination with ezrin to regulate microvilli function. Co-IP mass spectrometry and immunofluorescence identified SLC9A3R1 as the protein functioning in synergy with ezrin in early bovine embryos. Gain-of-function studies showed that miR-183 significantly improved developmental competence of SCNT embryo in terms of cleavage (76.63% vs 64.32%, p<0.05), blastocyst formation (43.75% vs 28.26%, p<0.05), apoptotic index (5.21% vs 12.64%, p<0.05), and the trophoblast ratio (32.65% vs 25.58%, p<0.05) in day 7 blastocysts. Conclusions: In conclusion, the present studies indicated that sperm-borne miR-183 might influence the formation of microvilli and embryo development by regulating expression of EZR mRNA.