Expression of bovine NPM2 mRNA and protein during oocyte maturation and early embryonic development. A. Real time PCR analysis of bovine NPM2 mRNA expression during in vitro oocyte maturation and early embryogenesis (mean ± SEM, n = 4 pools of oocytes or embryos). The oocytes and embryo samples used in the experiment included GV- and MII-stage oocytes, pronuclear (PN), 2-cell (2C), 4-cell (4C), 8-cell (8C), 16-cell (16C), morula (MO)-stage, and blastocyst (BL)-stage embryos. Data were normalized relative to abundance of GFP RNA (exogenous control). Different letters indicate statistical difference (P < 0.05). B. Determination of bovine NPM2 protein expression in GV- and MII-stage oocytes, and early embryos at 2-cell, 16-cell and blastocyst stage by Western blot analysis using anti-bovine NPM2 antibodies.