The Role of BRCA1-Dependent Ubiquitination in Breast Cancer
Abstract
Mutational inactivation of the breast cancer susceptibility gene, BRCAl, accounts for a large percentage of hereditary breast cancer. Recently, the highly conserved ring finger domain of BRCAI has been shown to function as an ubiquitin protein ligase or E3 in the ubiquitination of model substrates. Our hypothesis is that BRCAI effects the ubiquitination of proteins that are either negative regulators of DNA repair or are positive regulators of growth proliferation, leading either to their degradation or to an alteration of their activity. A major advancement in the understanding of BRCAI and its putative E3 activity, would be the identification of bonafide BRCAI substrates. To this end, we have generated the reagents to reconstitute BRCAI-dependent ubiquitination in vitro using El, E2 (UbcH5b), and full-length baculovirus-expressed BRCAI and BARD 1. It is expected that only full-length BRCA1 and BARD I proteins will confer physiologically relevant substrate specificity. We are currently testing Estrogen Receptor a, RNA Polymerase II large subunit, and BRCAI- interacting proteins as potential BRCA1/BARDI substrates. We are also generating stable cell lines which express epitope-tagged BRCAI for the purification of the BRCA1 E3 complex from mammalian cells and we are developing an in vivo assay for the identification of potential BRCAI/BARD1 substrates.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 2002
- Accession Number
- ADA407293
Entities
People
- P. R. Yew
Organizations
- University of Texas at San Antonio