Expression analysis of homeobox gene family in bovine pre- and post-implantative developmental stages

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Our goal has been aimed to do a molecular examination of these homeobox family members, which are differentially expressed during the early embryonic development and periimplantation. With this purpose, we would like to enrich our group of knowledge in the molecular reproduction, which helps to understand these natural or abnormal developmental phenomena, frequently caused by the pressure of the oocyte or the embryonic surroundings (Gandolfi et al. 2005). Because such stress conditions have been seen to drive placental defects, postnatal oversize or overweight (LOS), as well as organs failures in the offspring, still as adult diseases (Young et al. 1998). On this hand a lot of effects in the molecular biology could be related with these developmental mechanisms involved in the mammalian reproduction (McEvoy et al. 2001, 2003, Farin et al. 2006, Laurincik et al. 2003, Lonergan et al. 2003a, b, 2004, 2006, Wrenzycki et al. 2005b, Ecker et al. 2004). Many studies have been abundantly realized in the Homeobox mRNA and protein expression around implantation, as well as during primary differentiation events in the early mammalian development, also after blastocyst expansion, gastrulation, primitive streak formation, embryonic disk proliferation, organogenesis and limbogenesis (Beck et al. 1995, 1999, 2000, Charité et al. 1998, Chawengsaksophak et al. 1996, 1997, 2004, Deschamps et al. 1999, Manzanares and Krumlauf 2000). All these works have been focussed to determine the expression of Hox genes combination as well known as the Hox-code. This network appears to be very important in the spatial and temporal co- linearity during the early body patterning (Deschamps et al. 1999). Still, a lot of works have been directed on the mRNA and protein expression of the caudal members (Cdx) transcription factors as regulators of the Hox-gene expression among other genes, recently well reviewed by Deschamps and van Nes (2005) and Grier et al. (2005). The A-P patterning and the body-tissue identity of the mammalian embryo, as by others living beings, are directed by the interaction of the nuclear transcription factors as the homeodomain related proteins activity (van Nes et al. 2006, Pilon et al. 2006). The stress by surroundings appears to be highly related to placental and body-tissue development defects (Hall et al. 2005).