Expression and characterisation of the maternal factor Zygote arrest 1 (Zar1) gene in chicken tissues and embryos

Zygote arrest 1 (Zar1) is an oocyte-specific maternal effect gene that plays essential role during the oocyte-to-embryo transition in many species including human, mouse, rat, bovine, pig, frog and zebrafish. This study reports that this maternal-effect gene is also conserved in the avian species, namely the chicken Gallus gallus domesticus. In silico mining of the chicken genome shows that the chicken Zar1 (cZar1) gene consists of four exons and three introns, and the coding region of this gene is 903 bp. Using rapid amplification of cDNA ends analysis, the 3'-untranslated regions of the gene were isolated, where putative Pumilio (XPum) recognition sites as well as hexamer polyadenylation signals were identified. The gene is predicted to encode a 33 kDa protein, characterized by a conserved C-terminal FYVE/PHD zinc finger domain. In the present study the expression profile of this gene in chicken tissues and embryos was analyzed using reverse transcription-polymerase chain reaction (RT-PCR). The data presented in this study suggests that Zar1 is conserved in another vertebrate species, the chicken, and is preferentially expressed in the chicken reproductive tract, oocytes and embryos, suggesting a role in reproduction and embryonic development.