title: BRCA1 is a cell cycle-regulated nuclear phosphoprotein.
abstract: We have characterized the BRCA1 gene product by using four polyclonal antibodies raised against peptides from four different regions of the protein. The antibodies specifically recognize an approximately 220-kDa BRCA1 protein that is predominantly expressed in the nucleus of both normal and neoplastic breast cancer cells. It is a serine phosphoprotein that undergoes hyperphosphorylation during late G1 and S phases of the cell cycle and is transiently dephosphorylated early after M phase. We propose that BRCA1 is a phosphoprotein that alters in a qualitative and quantitative manner during cell cycle progression.
authors.affiliation: Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA.
authors.forename: H
authors.initials: H
authors.lastname: Ruffner
authors.forename: I M
authors.initials: IM
authors.lastname: Verma
mesh_terms: D000906:Antibodies; D019313:BRCA1 Protein / Q000502:physiology*; D001943:Breast Neoplasms / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000502:physiology*; D005260:Female; D006367:HeLa Cells; D006801:Humans; D009687:Nuclear Proteins / Q000502:physiology*; D010750:Phosphoproteins / Q000502:physiology*
chemical_list: D000906:Antibodies; D019313:BRCA1 Protein; D018797:Cell Cycle Proteins; D009687:Nuclear Proteins; D010750:Phosphoproteins