ChIP-seq of H3.3K4A/K36A mutant ESCs 2

Study to investigate the role of histone residues H3K4 and H3K36 for gene expression, histone localization and neuronal lineage specification by mutation of K4 and K36 in H3.3 to alanine. Histone variant H3.3 differs from the canonical H3.1/H3.2 by only 4 to 5 amino acids, which are necessary for nucleosome assembly independent of DNA replication, and is encoded by two gene copies. Complete loss of the two H3.3 genes (H3f3a and H3f3b) leads to embryonic lethality while single gene knockout yields viable mice. We used CRISPR-Cas9 to delete H3f3a and introduce homozygous point-mutations into H3f3b, thus ensuring that the entire pool of H3.3 protein carries the mutation of interest. We differentiated H3.3ctrl (H3f3a knock-out; H3f3b wild type), H3.3K4A mutant (H3f3a knock-out; H3f3b K4A) and H3.3K36A mutant (H3f3a knock-out; H3f3b K36A) ESCs into glutamatergic neurons. Genomic localization of H3.3 protein was determined by ChIP-Sequencing in ESCs (D0). Distribution patterns of RNA Polymerase II Phosphorylated on Serine 5 (RNA Pol II Ser5P), of histone modification H3K27me3 and chromatin remodeler components Brg1/Smarca4 (Swi/Snf) and Chd4 (NuRD) were measured by ChIP-Sequencing in ESCs (D0) to assess the impact of the H3.3K4A mutation on the epigenetic landscape. Distribution patterns of H3.3 were assessed by ChIP-Sequencing in HEK293T cells after depletion of Brg1/Smarca4 (Swi/Snf) and Chd4 (NuRD).