The BRCA1 and BARD1 association with the RNA polymerase II holoenzyme.
We have previously shown that endogenous BRCA1 and overexpressed epitope-tagged BRCA1 are present in the transcription complex called the RNA polymerase II holoenzyme (holo-pol). In this study, we further characterized BRCA1 association with the holo-pol by overexpressing deletion mutants of epitope-tagged BRCA1. We found that BRCA1-associated RING domain protein (BARD1) is a component of the holo-pol complex. Deletion of the BRCA1 NH(2) terminus, which is bound by BARD1 as well as other proteins, eliminates >98% of BRCA1 association with the holo-pol. In contrast with earlier observations, deletion of the COOH terminus of BRCA1 did not affect significantly the association with holo-pol. Immunocytochemistry of expressed full-length and deletion mutants of BRCA1 showed that the NH(2) terminus of BRCA1 is important for nuclear dot formation in S-phase. An intact BRCA1 NH(2) terminus is required for the association with holo-pol and for subnuclear localization in S-phase foci. Taken together, these data support a role for BRCA1 regulation of holo-pol function.
Chiba
Natsuko
N
Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
Parvin
Jeffrey D
JD
D000256:Adenoviridae / Q000235:genetics; D019313:BRCA1 Protein / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D002460:Cell Line; D000939:Epitopes; D017353:Gene Deletion; D020035:Holoenzymes / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D012319:RNA Polymerase II / Q000378:metabolism*; D016196:S Phase / Q000502:physiology; D025521:Tumor Suppressor Proteins; D044767:Ubiquitin-Protein Ligases
D019313:BRCA1 Protein; D002352:Carrier Proteins; D000939:Epitopes; D020035:Holoenzymes; D025521:Tumor Suppressor Proteins; C102449:BARD1 protein, human; D044767:Ubiquitin-Protein Ligases; D012319:RNA Polymerase II