Quantitative expression of candidate genes for developmental competence in bovine two-cell embryos

Abstract

Only competent oocytes are able to undergo complete maturation and normal embryonic development. Therefore, the identification of genes that are differentially expressed in competent oocytes would contribute to our understanding of the factors controlling competency. It is well known that time of cleavage after insemination in vitro is highly correlated with embryonic developmental potential and this can be used to distinguish between oocytes of different quality. The main objective of this study was to identify genes associated with competency and rapid cleavage. We examined the expression of 16 candidate genes (IDH, YEAF Cathepsin B, RAD50, TCP1 NCOR1, HUEL, STK6, ZNF403, AOP2, EEF1A1, Hsp90, Hsp40, AKR1B1, PGRMC1, and DMRT2) in early and late cleaving embryos, by real time PCR. These transcripts were derived from previous study in our laboratory using cDNA coming from a suppressive subtraction hybridization (SSH) between early cleaving versus late cleaving embryos spotted on a microarray slide. Of the 16 genes evaluated, 3 (IDH, YEAF, and H2A) showed statistical difference (P < 0.05) between early and late cleaving embryos. However, some genes such as Cathepsin B (P = 0.0677), RAD50 (P = 0.0899), and TCP1 (P = 0.0824) tended to show higher expression in the early cleaving than in the late cleaving embryo. In conclusion, we have identified three genes (YEAF, IDH, H2A) that were differentially expressed in the early cleaving embryos, and their expression can be associated with greater developmental competence.

Temporal detection of caspase-3 and -7 in bovine in vitro produced embryos of different developmental capacity

“…Fast cleaving bovine embryos have an altered gene expression (Lonergan et al 2000, Ward et al 2001, Gutiérrez-Adán et al 2004, Dode et al 2006 or altered polyadenylation status of several developmentally important gene transcripts (Pocar et al 2001, Brevini-Gandolfi et al 2002 and a higher chance of reaching advanced developmental stages in comparison with late cleaving embryos (Van Soom et al 1992, Dinnyés et al 1999, Lequarré et al 2003, Favetta et al 2004, Gutiérrez-Adán et al 2004. Studies investigating the effect of developmental kinetics on the incidence of apoptosis during preimplantation embryo development in bovine are scarce.…”

“…It is our hypothesis that fast cleavers contain all the necessary gene products and proteins to support further development without any problems, whereas a lack of some gene products and proteins in slow cleavers could be related to a higher chance to go into developmental arrest or apoptosis. Many gene products such as histones 2A and 3A, YEAF, cathepsin B, and chaperonines TCP1, which are involved in genome regulation and transcription, protein turn-over, cell metabolism, and cytoskeletal organization, are expressed at higher levels in fast cleavers in comparison with slow cleavers (Kanka 2003, Vigneault et al 2004, Dode et al 2006). More importantly, we hypothesized that fast cleaving embryos may have a better cellular defense against oxidative stress, as was demonstrated by the higher expression of IDH and RAD50 (Dode et al 2006).…”

“…Many gene products such as histones 2A and 3A, YEAF, cathepsin B, and chaperonines TCP1, which are involved in genome regulation and transcription, protein turn-over, cell metabolism, and cytoskeletal organization, are expressed at higher levels in fast cleavers in comparison with slow cleavers (Kanka 2003, Vigneault et al 2004, Dode et al 2006). More importantly, we hypothesized that fast cleaving embryos may have a better cellular defense against oxidative stress, as was demonstrated by the higher expression of IDH and RAD50 (Dode et al 2006). Both genes are involved in the stress protection of embryos, since IDH, a NADPC-dependent isocytrate dehydrogenase modulates oxidative damage and RAD50 is involved in the DNA double-strand break repair (Lee et al 2002, Huang & Dynan 2002).…”

“…Both genes are involved in the stress protection of embryos, since IDH, a NADPC-dependent isocytrate dehydrogenase modulates oxidative damage and RAD50 is involved in the DNA double-strand break repair (Lee et al 2002, Huang & Dynan 2002). Besides the lower expression level of some specific genes, gradual degradation of maternal mRNA (Dode et al 2006) or lack of essential survival and growth factors and cytokines released by maternal cells (Brison & Schultz 1997, Hardy 1999, Spanos et al 2000, Sjöblom et al 2005 can also be related to lower developmental competence and/or higher incidence of apoptosis in late cleaving embryos.…”

Biological differences between in vitro produced bovine embryos and parthenotes

“…PGRMC1 is a membrane-bound progesterone receptor that mediates anti-apoptotic effects of progesterone in granulosa cells (Engmann et al 2006. Bovine embryos at early cleavage stages (Dode et al 2006) and rat oocytes ) express PGRMC1. The role of PGRMC1 in development seems to be related to pregnancy recognition.…”