The Expression Of Oct 4 And Caspase 6 In Yak Oocytes And Early Embryo Development And The Effect Of Lif On Its Expression In Oocytes

The aim of this study was to explore the effect of octamer-binding transcription factor 4(Oct 4)and Cysteinyl aspartate specific proteinase 6(Caspase 6)during yak oocytes maturation and embryos development,which achieved by examined the expression of transcription factors Oct 4(octamer-binding transcription factor 4)and Cysteinyl aspartate specific proteinase 6(Caspase 6)at different stages.In this study,yak Cumulus-Oocyte Complexes(COCs)were collected and matured in vitro,the embryos produced by the method of in vitro fertilization(IVF)and the development competence of oocytes and embryos at different stages were evaluated.The expression and distribution of Oct 4 and Caspase 6 in the level of m RNA and protein in COCs and embryos at different stages were detected by Quantitative Real-time PCR(q RT-PCR)and indirect immunofluorescence.Based on the above studies,we supplied different concentration of LIF to COCs cultured in vitro,detecting the expression levels of Oct 4 and Caspase 6 in different groups by q RT-PCR and indirect immunofluorescence,which was to investigate the regulation function of LIF on the maturation process of yak oocytes.The results showed as follows:(1)The rates of embryos developed to stages of 2-4 cells,5-8 cells,9-16 cells and blastocyst cultured in vitro were 64.66±1.76%,43.33±1.76%,24.66±2.40%,9.33±0.6%,respectively.(2)The expression of Oct 4 and Caspase 6 gene could be detected at all stages during yak oocytes maturation and embryos development,which was highest in 9-16 cells embryos,followed by blastocyst,2-4 cells embryos and 5-8 cells embryos,while it was lowest in immature COCs and mature COCs.(3)The protein of OCT 4 is mainly distributed in the cytoplasm of COCs and embryos,which is weaker in the nucleus;The IOD of 9-16 cells embryos was highest,followed by blastocyst,2-4 cells embryos,which was lowest in 5-8 cells embryos;The protein of CAS6 is distributed in the cytoplasm of COCs.(4)The up-regulation of LIF concentration can promote the expression of Oct 4and reduce the expression of Caspase 6.The best concentration of LIF is 100 ng?m L-1.The study shows that Oct 4 could expressed in various periods of yak oocytes and embryo development,while the levels of Oct 4 were different,which detects that LIF can influence the expression of Oct 4 and Caspase 6 in process of oocytes maturation.The results in this study provide theoretical foundation to explore the functions of LIF during yak oocytes maturation process,which benefits the technique of yak oocytes In vitro fertilization and early embryo cultured in vitro.