BRCA1 can stimulate gene transcription by a unique mechanism

Most familial breast and ovarian cancers have been Linked to mutations in t he BRCA1 gene. BRCA1 has been shown to affect gene transcription but how it does so remains elusive. Here we show that BRCA1 can stimulate transcripti on without the requirement for a DNA-tethering function in mammalian and ye ast cells. Furthermore, the BRCA1 C-terminal region can stimulate transcrip tion of the p53-responsive promoter, MDM2. Unlike many enhancer-specific ac tivators, non-tethered BRCA1 does not require a functional TATA element to stimulate transcription. Our results suggest that BRCA1 can enhance transcr iption by a function additional to recruiting the transcriptional machinery to a targeted gene.