question: Which post-translational histone modifications are characteristic of facultative heterochromatin?
answer: Nuclear VapB methyltransferase diminishes the establishment of facultative heterochromatin by decreasing histone 3 lysine 9 trimethylation (H3K9me3). Dramatic changes in exposure of a repressive chromatin mark, H3K9me2, indicate that during development linker histone plays a role in establishing the facultative heterochromatin territory and architecture in the nucleus. Histone H3 trimethylation at lysine 36 is associated with constitutive and facultative heterochromatin.