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BRCA1 transcriptional activity is enhanced by interactions between its AD1 domain and AhR.
- Source :
-
Cancer chemotherapy and pharmacology [Cancer Chemother Pharmacol] 2008 Nov; Vol. 62 (6), pp. 965-75. Date of Electronic Publication: 2008 Feb 08. - Publication Year :
- 2008
-
Abstract
- Purpose: We previously reported that BRCA1 interacts with aryl hydrocarbon receptor nuclear translocator (ARNT) and that this interaction affects TCDD-induced CYP1A1 gene expression (Kang et al., J Biol Chem 281:14654-14662, 2006). In this study we continue this investigation and begin to define the significance of this interaction for the regulation of stress-induced transcription.<br />Methods: Immunoprecipitations (IPs), western blot (WB) analysis, GST pull-down assays and promoter reporter assays were used to investigate whether the aryl hydrocarbon receptor (AhR) can regulate transcription that is dependent on the activation domain 1 (AD1) domain of BRCA1.<br />Results: We show that AhR, a transcription factor, can bind specifically to AD1 in the C-terminal region of BRCA1 and affect BRCA1's ability to regulate transcription activity. We found that xenobiotics that positively and negatively affect AhR's activity as a transcription factor (e.g., dioxin and alpha-naphthoflavone, respectively), have similar effects on AhR's ability to affect AD1-domain-dependent transcription. These physical and functional AhR-AD1 interactions may require the coiled-coil motif in AD1 because point-mutations in this motif reduce these interactions.<br />Conclusion: Xenobiotic-activated AhR can function in two ways, as a component of the AhR/ARNT transcription factor and a regulator of AD1-dependent transcription. Consequently, BRCA1 has two distinct mechanisms for sensing xenobiotics and regulating AhR-dependent stress responses to these xenobiotics. We speculate that the normal functioning of this interaction could play a role in BRCA1's tumor suppressing ability.
- Subjects :
- BRCA1 Protein pharmacology
Benzoflavones pharmacology
Binding, Competitive
Cell Line, Tumor metabolism
Gene Expression Regulation, Neoplastic drug effects
Genes, Reporter
Humans
Neoplasm Proteins pharmacology
Polychlorinated Dibenzodioxins pharmacology
Protein Binding
Protein Interaction Mapping
Protein Structure, Tertiary
Proto-Oncogene Proteins c-jun metabolism
Receptors, Aryl Hydrocarbon drug effects
Transcription, Genetic drug effects
BRCA1 Protein chemistry
Gene Expression Regulation, Neoplastic physiology
Neoplasm Proteins chemistry
Receptors, Aryl Hydrocarbon chemistry
Transcription, Genetic physiology
Subjects
Details
- Language :
- English
- ISSN :
- 1432-0843
- Volume :
- 62
- Issue :
- 6
- Database :
- MEDLINE
- Journal :
- Cancer chemotherapy and pharmacology
- Publication Type :
- Academic Journal
- Accession number :
- 18259752
- Full Text :
- https://doi.org/10.1007/s00280-008-0686-x