NDF/GLYR1 Promotes RNA Polymerase II Processivity via Pol II Binding and Nucleosome Destabilization
The Nucleosome Destabilizing Factor (NDF) facilitates transcription through chromatin, but its precise mechanism remains incompletely understood. Here, we identify a critical region (amino acids 140-160) within NDF that specifically interacts with phosphorylated RPB1, the largest subu-nit of elongating RNA Polymerase II (Pol II). Mutations in this region disrupt Pol II interaction and impair Pol II elongation both in vitro and in cells, yet do not affect NDF's ability to destabilize nu-cleosomes, establishing a functional separation between these two activities. Cellular studies re-veal that NDF knockout cells display faster Pol II elongation rates but produce fewer nascent tran-scripts, demonstrating NDF's primary role in maintaining transcriptional processivity through-out gene bodies. Our findings demonstrate that NDF uses distinct mechanisms to ensure productive transcription elongation rather than simply enhancing elongation speed, offering new insights in-to how transcription efficiency is maintained in chromatin. Overall design: ChIP-seq analysis of NDF in NDF WT, MT2 and MT4 rescued SW480 KO cells; ChIP-seq analysis of Pol II in NDF WT and KO Hela cells across the conditions: DRB transcription arrested, DRB released for 5, 10 and 20 mins respectively.