Expression of homeobox-containing genes in cDNA libraries derived from cattle oocytes and preimplantation stage embryo

Abstract

The homeobox-containing gene family plays a pivotal role in regulating, patterning, and axial morphogenesis in the developing embryo. But there is still very little known about the expression and function of these genes in mammalian oocytes and preimplantation stage embryos. In this study we have used degenerate primers corresponding to the highly conserved regions of Antennapedia class homeodomains as a rapid and an efficient method to survey bovine cDNA libraries derived from unfertilised oocytes, single 2-cell, 4-cell, 8-cell, morula, and blastocyst stage embryos for the presence of homeobox sequences. Our results provide, for the first time, evidence for the transcription of Hoxa3 and Hoxd1 in oocytes; Cdx1 and Cdx2 in the 2-cell; Cdx1, Hoxa1, Hoxd1, and Hoxd4 in the 4-cell; Cdx1, Hoxa1, and Hoxc9 in the 8-cell; Cdx2, Hoxb9, and Hoxc9 in the morula; Cdx2, Hoxb7, Hoxb9, and Hoxc9 in blastocyst stage cattle embryos. These are candidate genes for the developmental capacity of in vivo and in vitro produced bovine embryos.