title: Evidence for a transcriptional activation function of BRCA1 C-terminal region.
abstract: Mutations in BRCA1 account for 45% of families with high incidence of breast cancer and for 80-90% of families with both breast and ovarian cancer. BRCA1 protein includes an amino-terminal zinc finger motif as well as an excess of negatively charged amino acids near the C terminus. In addition, BRCA1 contains two nuclear localization signals and localizes to the nucleus of normal cells. While these features suggest a role in transcriptional regulation, no function has been assigned to BRCA1. Here, we show that the C-terminal region, comprising exons 16-24 (aa 1560-1863) of BRCA1 fused to GAL4 DNA binding domain can activate transcription both in yeast and mammalian cells. Furthermore, we define the region comprising exons 21-24 (aa 1760-1863) as the minimal transactivation domain. Any one of four germ-line mutations in the C-terminal region found in patients with breast or ovarian cancer (Ala-1708-->Glu, Gln-1756 C+, Met-1775-->Arg, Tyr-1853 ->Stop), had markedly impaired transcription activity. Together these data underscore the notion that one of the functions of BRCA1 may be the regulation of transcription.
authors.affiliation: Laboratory of Molecular Oncology, Rockfeller University, New York, NY 10021, USA.
authors.forename: A N
authors.initials: AN
authors.lastname: Monteiro
authors.forename: A
authors.initials: A
authors.lastname: August
authors.forename: H
authors.initials: H
authors.lastname: Hanafusa
mesh_terms: D000818:Animals; D019313:BRCA1 Protein / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D001943:Breast Neoplasms / Q000235:genetics; D019556:COS Cells; D002460:Cell Line; D003001:Cloning, Molecular; D017931:DNA Primers; D004268:DNA-Binding Proteins; D005091:Exons; D005260:Female; D005656:Fungal Proteins / Q000096:biosynthesis; D006801:Humans; D007700:Kinetics; D008156:Luciferases / Q000096:biosynthesis; D016297:Mutagenesis, Site-Directed; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D018411:Spodoptera; D014157:Transcription Factors / Q000378:metabolism*; D015533:Transcriptional Activation; D014162:Transfection; D001616:beta-Galactosidase / Q000096:biosynthesis
chemical_list: D019313:BRCA1 Protein; D017931:DNA Primers; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C052130:GAL4 protein, S cerevisiae; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D008156:Luciferases; D001616:beta-Galactosidase