Fig. 6

Negative directionality index inversion sites are depleted of three CTCF classes but not the convergent patterns. a–c Enrichment of a CTCF binding sites, b CTCF site orientation and c CTCF orientation classes along the length of a meta-TAD based on the TAD collection reported by Javierre et al. [12]. Each TAD was divided into 100 bins, and the average number of CTCF sites was computed for each bin. d–f As for a–c but for 500-kb windows centred on the negative (+) to (−) points of inversion of directionality index showing d the average number of CTCF sites, e CTCF site orientation and f CTCF orientation classes per 5-kb bins. g Distribution of Forward (>, blue) and Reverse (<, red) CTCF sites in 1-Mb window from DI negative inversion points. On the left panel, the positive DI regions extracted from the TADs of GM12878 are ordered by their length from top to bottom and aligned with the negative inversion point to the right. On the right panel, the negative DI regions are ordered by their length from top to bottom and aligned with the negative inversion point to the left. Note that TADs are in general not symmetric with respect to their negative inversion point, as positive and negative DI regions in general have different lengths (see also Additional file 1: Fig. S9A-C)