Figure 2

Immunolabeling of metaphase chromosomes from human lymphoblastoid cells with antisera to H3K27ac, H3K27me3, H4K8ac and H4K20me3. (a) Immunostained karyotype from a metaphase chromosome spread immunostained with antibodies to H3K27ac (fluorescein isothiocyanate (FITC), green) and counterstained with DAPI (pseudocolored red). (b) Immunostained karyotype from a metaphase chromosome spread immunostained with antibodies to H3K27me3 (FITC, green) and counterstained with DAPI (pseudocolored red). (c) Metaphase chromosome spread immunostained with antibodies to H4K8ac (FITC, green) and counterstained with DAPI (pseudocolored red). Note the complete absence of FITC labeling at centric (constitutive) heterochromatin and the facultative heterochromatin of the inactive X (Xi). (d) Metaphase chromosome spread immunostained with antibodies to H4K20me3 (FITC, green) and counterstained with DAPI (pseudocolored red). Note the extensive, patchy staining of the interphase nucleus on the right. The arms of the Y chromosome (indicated) are labeled but its centric heterochromatin is not.