The MRNA Expression Of Interferon-tau Gene In Bovine Embryos From Different Methods

Interferon-tau (IFN- τ ) is the earliest pregnant signal from ruminant early embryos to maternal uterus. In this research, in situ hybridization (ISH) method was used to analyze the mRNA expression of IFN-τ in bovine embryos produced from different methods including parthenogenetic activation (PA), in vitro fertilization (IVF) and somatic cell nuclear transfer (NT). The embryos were recovered from different methods on day 3,4,5,6,7 and 9 after activation or insemination repectively. The results from in situ hybridization with Digoxingenin tagged DNA probe showed that the transcripts of IFN- τ gene appeared in IVF embryos on day 4, as well as in NT embryos on day 5. However the transcripts were not detected until day 6 in PA embryos. The IFN- τ mRNA abundance existed difference between IVF and NT embryos on day 5. The positive signals in NT blastocyst were higher than PA blastocyst on day 7.The mRNA expression of IFN- τ in PA, IVF, frozen-thawed IVF and NT bovine blastocysts on day 7 were compared by semi-quantitative RT-PCR. The result showed that the UV intensity ratios of IFN- τ fragment and β -actin by agrose gel scanning did not exist statistical difference among IVF, NT and PA embryos (P>0.05). However, abundance of IFN- τ mRNA in IVF blasocysts was highest, while abundance of IFN- τ mRNA in frozen-thawed IVF blastocysts was the lowest in these four gruops. At the same time, the mRNA expression of IFN- τ in frozen-thawed IVF and in vivo fertilization bovine embryos on day 7 were compared. The result showed that abundance of IFN- t mRNA in IVF blasocysts were higher than in vivo fertilization bovine embryos.