Expression of HDAC2 in <i>Hdac2^−/−</i> oocytes restores normal chromosome condensation and spindle formation in MII eggs.

<p>(A) Spindle morphology and chromosome alignment in MII eggs. Mutant oocytes were injected with a cRNA (0.4 µg/µl) encoding either <i>Egfp</i> (<i>Hdac2^−/−-</i>C) or <i>Hdac2</i> (<i>Hdac2^−/−-</i>OE) and incubated 24 h in CZB containing milrinone to prevent maturation; controls were wild-type oocytes injected with <i>Egfp</i> cRNA (WT- C). The oocytes were allowed to mature following transfer to milrinone-free medium overnight. MII eggs were fixed and stained with ß-tubulin antibody (red); DNA was counterstained with Sytox green (green). Shown are representative images. The bar corresponds to 10 µm. (B) Frequency of abnormal spindles and abnormal chromosome condensation in WT-C, <i>Hdac2^−/−-</i>C and <i>Hdac2^−/−-</i>OE MII eggs. 104 WT-C eggs, 104 <i>Hdac2^−/−-</i>C eggs and 76 <i>Hdac2^−/−-</i>OE eggs were analyzed respectively. *, p<0.05, χ².