VEGF promotes RNAPII pausing release through ETS1 to stimulate angiogenesis

RNA polymerase II (RNAPII) pausing release is a recently recognized checkpoint for transcriptional regulation. The biological roles of RNAPII pausing release and the mechanisms that by which extracellular signals control it are incompletely understood. Here we identify a novel mechanism by which VEGF stimulates RNAPII pausing-release through acetylation of ETS1, a master endothelial cell transcriptional regulator. In endothelial cells (ECs), ETS1 uniquely bound transcribed gene promoters and stimulated their expression by broadly increasing RNA polymerase II (RNAPII) pause release. VEGF enhanced ETS1 chromatin occupancy. Furthermore, VEGF increased ETS1 acetylation, enhancing its binding by BRD4 and thereby stimulating RNAPII pause release. This ETS1-mediated transduction of VEGF signaling to increase RNAPII pausing release was essential for EC angiogenic responses in vitro and in vivo. Together, our results define a new angiogenic pathway in which VEGF enhances ETS1-Brd4 interaction to broadly promote RNAPII pause release and drive angiogenesis. Overall design: ChiP-seq of ETS1 and Spike-in mRNA seq on HUVEC after VEGF stimulation at 0,1,4,12 hours. ChiP-seq of H3K27ac, H3K27me3, H3K4me1, 2, 3, H3K36me3, c-MYC, RNAPII on HUVEC after VEGF stimulation at 0 hour. ChiP-seq of RNAPII on HUVEC treated with GFP&ETS1 modified RNA, GFP& ETS1 siRNA. ERCC spike-in RNA-seq of HUVEC treated with GFP&ETS1 modified RNA.