Fig. 1. Histone H3K9 dimethylation spreads to ectopic locations in JIL-1 null and hypomorphic mutant backgrounds. (A-D) Polytene squash preparations labeled with anti-dmH3K9 antibody (red) and with Hoechst (DNA, blue). The upper panels show the anti-dmH3K9 labeling alone, whereas the lower panels show the composite images with the Hoechst labeling. The X chromosomes are indicated by X; the chromocenter with an arrow. In wild-type (wt) preparations, dmH3K9 labeling is mainly localized to the chromocenter (A). In JIL-1^z2/JIL-1^h9 (z2/h9, B) and in JIL-1^z2 homozygous (z2/z2) male (C) and female (D) mutants, the dmH3K9 labeling is clearly upregulated on the X chromosomes and to a lesser extent on the autosomes. In the JIL-1 mutants the morphology of the polytene chromosomes is perturbed with coiled and compacted chromosome arms. (E) The level of histone H3S10 phosphorylation is greatly decreased in JIL-1 null and hypomorphic alleles, whereas the levels of dmH3K9, HP1, histone H3 and tubulin are comparable to wild type. Immunoblots were performed on extracts from wild-type (wt), JIL-1^z2/JIL-1^h9 (z2/h9) and JIL-1^z2 homozygous (z2/z2) larvae. The immunoblots were labeled with anti-phospho-histone H3S10 (pH3S10), anti-dmH3K9, anti-HP1, anti-histone H3 (H3) and anti-tubulin antibodies.