Expression Of EnJSRV And IFN-τ In Reproduction Organs Of Mongolian Sheep In Early Pregnancy

ERV is derived from integration events during the evolution of ancient retroviruses into mammalian genomes over many millions of years. A distinctive feature of retroviruses is their presence as inherited elements in the germ line of most eukaryotes.These elements are transmitted through reproductive tract. The ovine genome contains27copies of endogenous retroviruses.The function of ERV is not clear in embryo development in early pregnancy. In this study, the technique of electrochemiluminescence was used to detect the content of progesterone in serum on pregnancy Day2,8,10,12,14,16,19,25and30.At the same time, endometrium,cervix, fallopian tube and vaginal epithelium of Mongolian sheep were separated and total RNA was extracted from these tissues. IFN-τ and enJSRV fragment were amplificated using RT-PCR. We detected the relative expression of enJSRV and IFN-τ mRNA in different tissues through Real-time quantitative RT-PCR. The relationship of the expression of enJSRV and IFN-τ mRNA in reproductive tract with progesterone content in serum was researched.Electrochemiluminescence results showed the progesterone level was0.4ng·mL-1on Day2and rose afterwards on Day8of gestation, then kept at about8.3ng·mL-1on Day8-16and decreased during Day19-30with the value2.5ng·mL-1on Day30. RT-PCR analyses displayed that enJSRV mRNA was expressed in the endometrium, cervix, fallopian tube and vaginal epithelium of Mongolian sheep and appeared the single strip, while IFN-τ only in the endometrium. Homology of enJSRV and IFN-τ is94.9%and96.3%respectively in GenBank.Real-Time PCR analyses demonstrated that enJSRV and IFN-τ mRNA were expressed specifically in uterine endometrium of Mongolian sheep. The mRNA expression level of enJSRV was high on Day12-14, while lower than the former on Day2-10and16-30during pregnancy. IFN-τ mRNA was expressed on Day12-25of gestation with the maximum value on Day14, and IFN-τ cannot be detected on Day30. And enJSRV mRNA was found to be expressed lower in the cervix on Day10, in fallopian tube on Day10,in vaginal on Day30.Whereas the expression was greater in the cervix on Day30,in fallopian tube on Day25, in vaginal on Day10and19.These results indicated that expression of enJSRV RNAs was detected in epithelia of oviduct, uterus, cervix, and vagina. And enJSRV was abundant and specific expression in the epithelia of ewe reproductive tract.The expression of enJSRV in endometrium was positively correlated with changes in peripheral blood progesterone content and IFN-τ. Furthermore enJSRV can play a significant role in reproductive biology and provide a theoretical basis during early pregnancy.