Immunodetection of ASH2, Sin3A and HCF on polytene chromosomes. (a) Images of all the chromosomes showing partial colocalization of Sin3A and HCF (top panel), Sin3A and ASH2 (central panel), and HCF and ASH2 (bottom panel). Note that only HCF is found in the chromocenter (C) and that no Sin3A is detected in chromosome 4 (4). (b) Details of the 2L chromosome arm. Sin3A, ASH2 and HCF staining does not overlap with DAPI (columns 1-3). Sin3A and HCF (top panel), ASH2 and Sin3A (central panel), and HCF and ASH2 (bottom panel) colocalize at many sites (columns 3-5). Green and red dots in columns 3-4 indicate strongly stained sites. Green and red dots in column 5 indicate a weak colocalization (more green staining or more red staining) and yellow dots indicate bands with strong colocalization. Arrowheads indicate sites of triple colocalization between ASH2, HCF and Sin3A. Antibodies used were anti-Sin3A, anti-HCF and anti-HA (for ASH2-HA detection).