Anti-BRD4 (301-985, Bethyl Laboratories) and anti-RNA Pol II (39097, Active Motif) Chromatin Immunoprecipitation was performed as previously described 33. Five independent 10-cm plates of ARVFs were combined per immunoprecipitation. Libraries were prepared using the Rubicon TruPLEX Tag-seq kit and submitted to the UC Denver Genomics and Microarray core facility for sequencing (HiSeq2000).