Figure 4

Expression of maternal and zygotic Dnmt1s during preimplantation development. A. Time course of Dnmt1s expression at defined preimplantation cleavage stages determined by immunostaining with the UPT82 antiserum. Mo = morula. Bl = blastocyst. B. Time course of Dnmt1s expression during preimplantation development in embryos derived from crosses between wild-type (+/+) female mice and homozygous Dnmt1^V/V(V/V) male mice. Inset is bright-field image of immunostained 1-cell embryo. C. Time courses of Dnmt1s expression during preimplantation development in embryos derived from crosses between heterozygous Dnmt1^V/+ (V/+) female mice and homozygous Dnmt1^V/V(V/V) male mice. The 4-cell and 8-cell embryos in the top row show primarily nuclear Dnmt1s staining whereas 4-cell and 8-cell embryos in the botton row show little or no nuclear Dnmt1s. All seven 2-cell, three out of seven 4-cell and six out of 13 8-cell embryos showed nuclear staining. Bar, 20 μm.