Project description:We identified genes expressed in mouse liver that are regulated by Cux2, a highly female-specific liver transcription factor whose expression is regulated by sex-dependent plasma GH patterns. Using siRNA to knockdown Cux2 expression in female liver, we show that female specific genes are predominantly repressed by Cux2 knockdown. In contrast, similar numbers of male-biased genes are repressed as are induced by Cux2 knockdown. A scrambled, non-specific siRNA was used as a control. (Published in: TL Conforto et al 2012, Mol Cell Biol. 2012, 32:4611-4627. PubMed PMID: 22966202; PMCID: PMC3486175)
Project description:Transcription factor access to regulatory elements is prevented by the nucleosome. Heat shock factor 1 (HSF1) is a winged helix transcription factor that plays roles in control and stressed conditions by gaining access to target elements, but mechanisms of HSF1 access have not been well known in mammalian cells. We show a physical interaction between the wing motif of human HSF1 and replication protein A (RPA), which is involved in DNA metabolism. Depletion of RPA1 abolishes HSF1 access to the promoter of HSP70 in unstressed conditions, and delays its rapid activation in response to heat shock. The HSF1-RPA complex leads preloading of RNA polymerase II and opens chromatin structure by recruiting a histone chaperone FACT. Furthermore, this interaction is required for melanoma cell proliferation. These results provide a mechanistic basis for constitutive HSF1 access to nucleosomal DNA, which is important for both basal and inducible gene expression. To examine whether the HSF1-RPA complex regulates the expression of genes, mRNA levels in MEFs with/without HSF1- or RPA1-shRNA were analyzed by DNA microarray analysis using GeneChip Mouse Gene 1.0 ST Arrays (Affymetrix).
