Fig. 5. Chromosome morphology and histone modifications. (A) The morphologies of mouse oocytes and injected donor nuclei are classified according to GV oocyte maturation status. Histone H3 methylation at lysine 9 (Me-H3-K9), phosphorylation at serine 10 (P-H3-S10) and serine 28 (P-H3-S28) of oocyte and somatic cell nuclei injected into intact and enucleated GV oocytes were examined simultaneously up to 17 hours after injection. (B) Expression of methylation H3-K9 in somatic nuclei injected into the cytoplasm (a-c) and nucleus (d-f), then cultured for 3 hours with dbcAMP. Control oocyte (g-i) was cultured same time without dbcAMP. Arrows indicate injected cumulus nuclei. (C) About 10% of enucleated GV oocytes extruded an extremely large first polar body at 17 hours after cumulus cell injection (c). Scale bar:20 µm.