The adenovirus E1A binding protein BS69 is a corepressor of transcription through recruitment of N-CoR

BS69 was first identified as a protein that interacts directly with the tra nsactivation domain (conserved region 3) of the 289R adenovirus type 5 E1A protein. We show here that BS69 is a potent repressor of transcription, BS6 9 mediates repression, at least in part, through interaction with the co-re pressor N-CoR, BS69 interacts with N-CoR through a MYND domain in its carbo xyl terminus, A recently cloned splice variant of BS69, designated BRAM1, i s also capable of interacting with N-CoR and E1A. but unlike BS69. is not a ble to repress transcription, indicating that N-CoR interaction is necessar y but not sufficient for BS69 repression, Expression of E1A inhibits repres sion mediated by BS69, Our data suggest that BS69 participates in transcrip tional repressor complexes and that E1A can modulate these complexes throug h interaction with BS69.