| Abstract | BRCA1 is a gene whose protein (also named BRCA1) is found throughout all human cells and engages in DNA repair, cell cycle regulation, gene transcription regulation, and apoptosis. However, mutations in BRCA1 typically confer a higher risk of cancer in estrogen-responsive tissues, including breast epithelial tissue. This increase in incidence of tissue-specific cancers is thought to be in part due to the role of BRCA1 in the estrogen-response pathway and interaction with the estrogen receptor alpha (ERa). Previous studies identified possible regions of each protein involved in the binding interface between BRCA1 and ERa. Using these regions (amino acids 177-240 in BRCA1 and the ligand binding domain of ERa) as our constructs, our studies further analyzed the molecular details of this direct interaction and determined methods conducive to studying the BRCA1-ERa interaction. A pull-down assay qualitatively confirmed binding between the constructs of BRCA1 and ERa. Data collected from NMR spectroscopy reaffirmed the direct interaction between BRCA1 and ERa first seen in the pull-down assay and provided evidence demonstrating that the presence of estrogen in the samples increased binding affinity. Finally, fluorescence spectroscopy of quenching experiments confirmed the previous results - that a direct interaction occurs between the constructs of BRCA1 and ERa used - and allowed us to describe the binding curve of the system being studied. The molecular details confirmed here provide further avenues of study, such as documenting variants of unknown significance or studying the role estrogen plays in the function of the BRCA1-ERa complex, which could lead to novel findings that expand our understanding of the role either protein plays in cancer development. |
