Mapping H3K4me3 enrichment upon LAD perturbation in early embryos.

We investigated whether LAD disruption phenotypes are associated with genome-wide changes in H3K4me3 enrichment. To do this, we focused on two pathways that produce distinct LAD phenotypes. The first is the constitutive heterochromatin pathway involving Suv39h1, Hp1a, and Hp1g (Pool J), which leads to the collapse of control LADs and causes LAD 'flattening' in 2-cell embryos. The second is the H3K9me2/K27me2 demethylase pathway involving Kdm7a, Kdm7c, and Lsd1 (Pool I), which causes the collapse of control 2-cell LADs through the formation of broad ectopic LADs. To examine changes in H3K4me3 under these perturbations, we performed CUT&Tag at the late 2-cell stage. Low-input CUT&Tag targeting H3K4me3 in late 2-cell stage embryos.