title: Profiling of the BRCA1 transcriptome through microarray and ChIP-chip analysis.
abstract: A role for BRCA1 in the direct and indirect regulation of transcription is well established. However, a comprehensive view of the degree to which BRCA1 impacts transcriptional regulation on a genome-wide level has not been defined. We performed genome-wide expression profiling and ChIP-chip analysis, comparison of which revealed that although BRCA1 depletion results in transcriptional changes in 1294 genes, only 44 of these are promoter bound by BRCA1. However, 27% of these transcripts were linked to transcriptional regulation possibly explaining the large number of indirect transcriptional changes observed by microarray analysis. We show that no specific consensus sequence exists for BRCA1 DNA binding but rather demonstrate the presence of a number of known and novel transcription factor (TF)- binding sites commonly found on BRCA1 bound promoters. Co-immunoprecipitations confirmed that BRCA1 interacts with a number of these TFs including AP2-α, PAX2 and ZF5. Finally, we show that BRCA1 is bound to a subset of promoters of genes that are not altered by BRCA1 loss, but are transcriptionally regulated in a BRCA1-dependent manner upon DNA damage. These data suggest a model, whereby BRCA1 is present on defined promoters as part of an inactive complex poised to respond to various genotoxic stimuli.
authors: Centre for Cancer Research and Cell Biology, Queen's University Belfast, Belfast BT9 7BL and ALMAC Diagnostics, Craigavon BT63 5QD, UK. j.gorski@qub.ac.uk
authors: Julia J
authors: JJ
authors: Gorski
authors: Kienan I
authors: KI
authors: Savage
authors: Jude M
authors: JM
authors: Mulligan
authors: Simon S
authors: SS
authors: McDade
authors: Jaine K
authors: JK
authors: Blayney
authors: Zhaoping
authors: Z
authors: Ge
authors: D Paul
authors: DP
authors: Harkin
mesh_terms: D019313:BRCA1 Protein / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000502:physiology*; D045744:Cell Line, Tumor; D047369:Chromatin Immunoprecipitation; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D006801:Humans; D020411:Oligonucleotide Array Sequence Analysis; D013312:Stress, Physiological / Q000235:genetics; D014157:Transcription Factors / Q000378:metabolism; D059467:Transcriptome
chemical_list: D019313:BRCA1 Protein; D014157:Transcription Factors