D. RNAchIP read density per kb on the indicated introns for input and IP in samples from both untreated and PMA stimulated cells, n=6 biological replicates, or 3-times randomized intervals, n=18 samples. Dots represent individual data points. HP1γ/KO introns are all 272 intronic intervals between exon junctions differentially detected in HP1γ and KO. Random introns are a matching library of random intronic intervals. E. RNAchIP read density per kb on the genes corresponding to the introns tested in (D), and analyzed as in (D), n=6 biological replicates, or 3-times randomized intervals, n=18 samples. Data information: All graphes represent mean and s.d. (** P < 0.005, ***P < 0.001; two-tailed Student's t-test). 