Figure 1

H3K9 acetylation patterns in oocytes and zygotes. In both mouse (a, a'-c, c') and sheep (d, d'-f, f'), GV-stage oocytes (a, d), MII-stage oocytes (b, e) and zygotes (c, f) were stained for H3K9 acetylation (ac-H3K9, green). The samples were counterstained with propidium iodide (PI, red) to visualize the DNA. Mouse GV nucleus showed positive staining for ac-H3K9 (a), but sheep GV nucleus showed no signal (d). In both species, MII-stage oocytes were negatively stained for ac-H3K9 (b and e). In zygotes (c and f), both parental pronuclei were intensively stained for ac-H3K9.