Fig. 3

SSRs are devoid of Pc protein while SNRs represent PRC1 domains. a SSRs (shaded in blue) are devoid of Pc binding as exemplified by 10 Mb span of chromosome 2L. SNRs (see text) match the Pc-bound domains (arrows). H3K27me3 profiles are presented as quantile normalized log₂(IP/inp) values. Pc DamID profiles are presented as log₁₀(P) units, where P—significance level assessed with Fisher’s exact test. Dotted lines designate FDR = 0.5 levels for Pc enrichment. Blue shading shows positions of SSRs, arrows point at SNRs. b Scatter plot of Polycomb DamID data in salivary glands of wild type strain and in SuUR mutants. SNRs are shown in blue while SSRs—in red. Pc DamID signal is presented as log₁₀(P) units, where P—significance level assessed with Fisher’s exact test. c Pc peak density in SSRs, SNRs and in 1000 random regions across the genome. SuUR mutation does not affect Pc distribution nor in SSRs nor in SNRs. d Scatter plot of quantile-normalized H3K27me3 ChIP-chip data in salivary glands of wild type strain and in SuUR mutants. SNRs are shown in blue while SSRs—in red. The scales are log₂(IP/inp) values. e Genomic regions corresponding to SSRs and SNRs in Kc167 cells show characteristic distribution of chromatin types according to the classification of [5]