Figure 5

DNMT3B methylates CpG islands in epiblast cells. (A) Boxplot showing the distribution of CpG methylation in the whole genome (400 bp tiles) and CGIs in WT, Dnmt3a-/- and Dnmt3b-/- E8.5 embryos. Only sequences with >50% methylation in WT E8.5 embryos are considered. (B) Representative examples of RRBS profiles at DNMT3B-dependent CGIs in WT, Dnmt3a-/- and Dnmt3b-/- E8.5 embryos in gene promoters (Sycp3, Dmrtb1, Mael) and gene bodies (Cux1, chr5:136,274,862-136,275,397; Bcl11b, chr12:107,915,284-107,917,294). (C) Dynamics of DNA methylation across embryonic development and in Dnmt3-mutant E8.5 embryos in slow (<20% methylation in E3.5, <50% in E5.5 and >50% in E8.5) and fast (<20% methylation in E3.5, >50% methylation in E5.5 and >50% methylation in E8.5) CGIs. (D) DNMT3B methylates pmCGIs, as illustrated by the RRBS profiles in E8.5 embryos at the Rbm46 CGI. The box plot shows the distribution of methylation at all pmCGIs in blastocysts (E3.5), WT E8.5 embryos and Dnmt3-mutant E8.5 embryos.