Inhibiting 3-phosphoglycerate kinase by EDTA stimulates the development ofthe cleavage stage mouse embryo

Addition of EDTA to the medium significantly enhances mouse embryo developm ent in culture. Embryos cultured in the absence of EDTA exhibit abnormal in creases in glycolytic activity that result in reduced development. Culture with EDTA was able to prevent this increase in glycolysis and, therefore, m aintain developmental competence. EDTA was shown to inhibit the activity of the glycolytic enzyme, 3-phosphoglycerate kinase. Additionally, the effect of EDTA on maintaining high rates of embryo development in culture could b e mimicked by the addition of Cibacron blue, an inhibitor of 3-phosphoglyce rate kinase. The inhibition of 3-phosphoglycerate kinase by EDTA could be o vercome by the addition of exogenous magnesium, indicating that the effect of EDTA was to reduce the availability of this co-factor to the glycolytic kinases. Embryos cultured with EDTA had significantly lower levels of intra cellular magnesium compared to embryos cultured without EDTA. Therefore, th e effect of EDTA appears to be as a chelator of divalent cations such as ma gnesium, that are required for normal activity of kinases such as 3-phospho glycerate kinase. Mol. Reprod. Dev, 60: 233-240, 2001. (C) 2001 Wiley-Liss, Inc.