The BARD1 (BRCA1-associated RING Domain 1) protein forms a heterodimeric complex with BRCA1. BARD1-bound BRCA1 is stabilized and recruited to the nucleus where the complex acts as a Ubiquitin E3 Ligase to function in DNA repair or cell survival pathways. One target of the BRCA1/BARD1 E3 Ligase activity, RNA Polymerase II, is degraded and subsequent transcription and RNA processing are inhibited. This allows time for repair of damaged DNA before cellular events progress.