RETINOBLASTOMA PROTEIN TETHERED TO PROMOTER DNA REPRESSES TBP-MEDIATED TRANSCRIPTION

The retinoblastoma (RB) tumour suppressor protein negatively regulates cell proliferation by modulating transcription of growth-regulatory g enes. Recruitment of Rb to promoters, by association with E2F complex or by fusion with heterologous DNA-binding domains, demonstrated that Rb represses directly transcription. Recent studies also suggest that the RE protein is able to repress gene transcription mediated by the R NA polymerase I and III. Since the TATA-binding protein (TBP) is an im portant component for transcription mediated by all three RNA polymera ses, we have analysed the functional interaction between Rb and TBP in vivo in the context of RNA pol II-driven transcription. We demonstrat ed that in mammalian cells Rb tethered to promoter represses TBP-media ted activation in vivo, and Rb-mediated repression is reversed in the presence of the inhibition of histone deacetylase activity by trichost atin A (TSA). J. Cell. Biochem. 70:281-287, 1998. (C) 1998 Wiley-Liss, Inc.