Brd2, a mitogen-activated kinase localized to the nucleus, is a putative transcriptional regulator which interacts with E2F1 and with histone H4 acetylated at ‘Lys-13’. It is expressed during development and may be involved in growth control. Brd2 also may play a role in spermatogenesis or folliculogenesis and may be involved in some types of leukemia and in juvenile myoclonic epilepsy.