Before revision:  Based on the ChAs of these epigenomic features calculated in 4 different interaction networks , we find Polycomb Group proteins and associated histone marks to play a prominent role. Remarkably, in promoter-centered networks, we observe higher ChAs of the actively elongating form of RNA Polymerase 2  compared to inactive forms  in interactions between promoters and other elements.
After revision:  Based on the ChAs of these epigenomic features calculated in 4 different interaction networks , we find Polycomb Group proteins and associated histone marks are the features with the highest chromatin assortativity in promoter-centred networks. We then ask which features distinguish contacts amongst promoters from contacts between promoters and other genomic elements. We observe higher chromatin assortativity of the actively elongating form of RNA Polymerase 2 compared to inactive forms in interactions between promoters and other elements.