Fig. 4.
Homolog pairing is related to Zld-mediated opening of chromatin. a Cis (upper panel) and trans-homolog (second panel from the top) contact maps of a 2 Mb region (2 R:16-18 Mb). Lower panels, pairing score (PS) calculated using a 28 kb window at 4 kb resolution (black), ChIP-seq profiles of Zld (dark purple)41, Bcd (green)40, GAF (blue)43, and Dl (brown)41. Gray boxes, regions associated with elevated PS values in boundaries. b Correlation analyses between the PS values and the binding profiles of Zld, Bcd, GAF, and Dl as determined using pairwise Spearman correlation. Control, randomized 200 kb chunks of the PS. Spearman correlation coefficients indicated in each box and by a heatmap; P-values in parentheses. c 25% of the strongest Zld binding coincides significantly with high PS regions, compared to the remaining Zld binding (*P < 10−10, Mood’s median test). d PS values vs loss of contact insulation upon Zld depletion, grouped by Zld binding strength quartile. Ovals represent the contours of 2D-Gaussian approximations, at a distance of 2 standard deviations from the mean (the dot). Regions with stronger Zld binding show both high PS values and increased loss of contact insulation upon Zld depletion. e Zld depletion affects insulation of domain boundaries at regions otherwise associated with high pairing. Thus, Zld may affect homologs to be further away from each other when insulation is lost