Cover image

The mammalian euchromatic histone H3 Lys 9 methyltransferase, G9a, is essential for normal embryonic development. Shown here are DAPI-stained transverse sections from an E8.5 wild-type (background) and an E9.5 G9a^/ (inset) mouse embryo. By E9.5, G9a^/ mouse embryos display severe developmental retardation, including incomplete anterior neural groove fusion (shown here), and early lethality. Mitotic cells are present in similar ratios between E9.5 G9a^/ and wild-type mouse embryos. However, a drastic accumulation of apoptotic cells is commonly observed in G9a^/ embryos, suggesting that the G9a^/ embryonic growth defect is, at least in part, due to apoptotic cell death. (For details, see Tachibana et al., p. 1779.)