GSE130947
Analyses of H2A and H2A.Z incorporations into chromatin of permeabilized cells
Histone proteins, including their variants, play indispensable roles in chromatin structure and function. The specific histone incorporation is the key to epigenetic features and contributes to cell differentiation and development. To understand how each histone is targeted to and incorporated into the specific chromatin region, we used a new method, in which we introduced epitope-tagged histone complexes in permeabilized cells and let them incorporated into the chromatin. The newly incorporated histone complex is easily distinguished from the parental histones by the epitope-tag. We name this as RhIP (Reconstituted histone complex Incorporation into chromatin of Permeabilized cell) assay. We analyzed the correlation between the histone incorporation and the chromatin structure, using the H2A-H2B and H2A.Z-H2B complexes. The histone incorporation mainly occurred at less condensed chromatin (open), suggesting that the condensed chromatin (closed) is a barrier for histone incorporation. To overcome this barrier, H2A, but not H2A.Z, uses a replication-coupled deposition mechanism. This led to the genome-wide distribution of H2A and the exclusion of H2A.Z from the closed chromatin. Overall design: RhIP-ChIP-seq of H2A and H2A.Z using asynchronous, early S and late S phase cells.