Micrornas Expression And Function Analysis In The Development Of Embryo In Different Situation

microRNAs (miRNAs)are non-coding21-23nucleotide RNA molecules that regulate the expressions of other genes expression a post-transcription level by inhibiting translation or cleaving complementary target mRNAs. By now, they have been reported to be involved in multiple biological processes, including epigenetic modification, cell proliferation, differentiation, apoptosis, stem cell pluripotency maintenance and tumor genesis.microRNAs are widely studied in model animal. However, microRNAs in livestock, like bovine, early embryo development remains elusive. Our study investigated the difference of miRNA expression profiles between the AI,IVF,PAand NTblastocysts. The NT blastocysts have the smallest microRNAs Transcriptome about only75%of the other threeaverage. The cluster miR-17-92is an outstanding one. The miR-19b appears just from the zygotic gene activation, during the8-16cell stage of bovine embryo. We predicted miR-19b target genes through4kinds of softwares. Though experimental verification, we found that Rap la may be a target of miR-19b and participate in the regulation of early embryo gene expression regulation. miR-19b regulates the early blastocysis process through the regulation of Rap la, and then affects the MAPK for methylation modification and cell cycle regulation.Our results suggest that nuclear transfer which is characterized by disoreder methylationmay result in insufficient expression of miR-19b when the zygotic gene activated in the cloned embryos, As a conclusion, taken together, the mir-19b is one of the key factors which can control the blastocysts quality. The transgenic somatic cells which overexpress the miR-19b in the special period may enjoy a higher successful rate.The lungs undergo changes that are adaptive for high elevation in certain animalspecies. Lowland chickenbreeds undergo physiological effects and suffer greater mortality when they areexposed to hypoxic conditions during embryonic development. Although thesephysiological effects have been noted, the mechanisms that are responsible forhypoxia-induced changes in lung development and function are not known. Here wehave examined the role of a particular microRNA (miRNA) in the regulation of lungdevelopment under hypoxic conditions. When chicks were incubated in low oxygen(hypoxia), miR-15a was significantly increased in embryonic lung tissue. Theexpression level of miR-15a in hypoxic Tibet chicken embryos increased and remainedrelatively high at embryonic day (E)16-20, whereas in normal chickens, expressionincreased and peaked at E19-20, at which time the cross-current gas exchangesystem (CCGS) is developing, bcl-2was a translationally repressed target of miR-15ain these chickens. In our study, thehypoxia-induced decrease in Bcl-2protein through the regulation of miR-15a and resulted in apoptosis in the mesenchymearound the migrating tubes, which led to an expansion and migration of the tubes thatwould become the air capillary network and the CCGS.