CDC73, Fig. 1

CDC73 is a member of the human PAF1 (RNA polymerase II-associated factor 1) transcriptional complex. Other human complex members include RTF1, SKI8, CTR9, LEO1, and PAF1 that associate with RNA polymerase II for transcriptional initiation and elongation. CDC73 is a binding partner of both E3 ubiquitin RING finger ligases RNF20 and RNF40 that function, along with an E2 conjugating enzyme, to add a single ubiquitin (represented as a red circle) to histone H2B at lysine 120 (H2Bub1). This monoubiquitination event facilitates decondensed, active chromatin, allowing RNA polymerase II to move along the gene, enacting transcriptional elongation. Nucleosomes, consisting of the core histone octamer (histones H2A, H2B, H3, and H4) are depicted as blue discs around which DNA is wrapped, constituting the chromatin. The histone H2B amino-terminal tail is shown protruding from this structure