Expression pattern of transcription factors during zygotic genome activation in buffalo (<i style="mso-bidi-font-style: normal">Bubalus bubalis</i>) embryos produced <i style="mso-bidi-font-style: normal">in vitro</i>

Abstract

Following fertilization, the early embryo is transcriptionally silent and early development is directed by the complement of maternally-inherited mRNAs and proteins. At some point, however, a maternal to embryonic transition occurs, in which further development is directed by the zygotic transcripts. So to determine this transition stage, the quantitative expression pattern of HMGN-2 and CREB genes involved in transcription activation, and two other genes, EHMT-1 and EHMT-2, involved in epigenetic modification were evaluated in different embryonic stages with and without different concentration of α-amanitin. The results of the present study showed that the mRNA transcripts of <i>EHMT-1, EHMT-2, HMGN-2 </i>and <i>CREB </i>were present in immature, <i>in vitro-</i>matured oocytes, and in embryos at 2-, 4-, 8- to 16-cell, morula and blastocyst stages. However, all these four genes showed very low levels around the 8- to 16-cell stage, and their levels increased by at least 80% at the blastocyst stage compared to those initially found in immature GV or <i>in vitro</i> matured oocytes, which indicates that the zygotic genome activation occurs at 8-16 cells stage in <i style="mso-bidi-font-style:normal">in vitro</i> produced buffalo embryo.<b style="mso-bidi-font-weight:normal"> </b>