This family includes the human RPAP2 (RNAP II associated polypeptide) protein and the yeast Rtr1 protein [1]. It has been suggested that this family of proteins are regulators of core RNA polymerase II function [1].

1: Rtr1 is the yeast homolog of a novel family of RNA polymerase II-binding proteins. Gibney PA, Fries T, Bailer SM, Morano KA; Eukaryot Cell. 2008; [Epub ahead of print] PMID:18408053