Chromatin interaction of TATA-binding protein is dynamically regulated in human cells
ABSTRACT Gene transcription in mammalian cells is a dynamic process involving regulated assembly of transcription complexes on chromatin in which the TATA-binding protein (TBP) plays a central role. Here, we investigate the dynamic behaviour of TBP by a combination of fluorescence recovery after photobleaching (FRAP) and biochemical assays using human cell lines of different origin. The majority of nucleoplasmic TBP and other TFIID subunits associate with chromatin in a highly dynamic manner. TBP dynamics are regulated by the joint action of the SNF2-related BTAF1 protein and the NC2 complex. Strikingly, both BTAF1 and NC2 predominantly affect TBP dissociation rates, leaving the association rate unchanged. Chromatin immunoprecipitation shows that BTAF1 negatively regulates TBP and NC2 binding to active promoters. Our results support a model for a BTAF1-mediated release of TBP-NC2 complexes from chromatin.
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- "Our studies were specifically aimed at tracking components of the core promoter regulatory factors and were instigated by the recent evidence that multisubunit transcription cofactors may play unexpectedly important regulatory roles during differentiation and development (for reviews, see D'Alessio et al. 2009; Goodrich and Tjian 2010; Muller et al. 2010). Although much has been gleaned regarding the regulatory functions of transcription cofactor complexes employing a combination of in vitro biochemical assays, in vivo RNAi functional assays, and structural analyses (Zhai et al. 2005; Marr et al. 2006; Liu et al. 2009), investigations have only recently been turned to how these key basal factors target specific genes in living cells (Giglia-Mari et al. 2009; de Graaf et al. 2010). Here, we observed the differential subnuclear distributions of general transcription factors TFIID and TAF3 relative to the nuclear periphery, which is correlated with selective core promoter factor occupancy at the promoter of MyoD, the master regulator of myogenesis . "
ABSTRACT: Recent findings implicate alternate core promoter recognition complexes in regulating cellular differentiation. Here we report a spatial segregation of the alternative core factor TAF3, but not canonical TFIID subunits, away from the nuclear periphery, where the key myogenic gene MyoD is preferentially localized in myoblasts. This segregation is correlated with the differential occupancy of TAF3 versus TFIID at the MyoD promoter. Loss of this segregation by modulating either the intranuclear location of the MyoD gene or TAF3 protein leads to altered TAF3 occupancy at the MyoD promoter. Intriguingly, in differentiated myotubes, the MyoD gene is repositioned to the nuclear interior, where TAF3 resides. The specific high-affinity recognition of H3K4Me3 by the TAF3 PHD (plant homeodomain) finger appears to be required for the sequestration of TAF3 to the nuclear interior. We suggest that intranuclear sequestration of core transcription components and their target genes provides an additional mechanism for promoter selectivity during differentiation.Genes & development 02/2011; 25(6):569-80. DOI:10.1101/gad.2021411 · 12.64 Impact Factor
Conference Paper: Ciset: a generalization of fuzzy sets[Show abstract] [Hide abstract]
ABSTRACT: In this paper we extend fuzzy theory to handle both positive and negative values. This would enable us to extend database theory and expert systems to integrate the supporting and the opposing facts based on the subject matter and thus obtain a complete picture of the situation.Fuzzy Information, 2004. Processing NAFIPS '04. IEEE Annual Meeting of the; 07/2004
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ABSTRACT: Histone methylation patterns are correlated with eukaryotic gene transcription. High-affinity binding of the plant homeodomain (PHD) of TFIID subunit TAF3 to trimethylated lysine-4 of histone H3 (H3K4me3) is involved in promoter recruitment of this basal transcription factor. Here, we show that for transcription activation the PHD of TAF3 can be replaced by PHDs of other high-affinity H3K4me3 binders. Interestingly, H3K4me3 binding of TFIID and the TAF3-PHD is decreased by phosphorylation of the adjacent threonine residue (H3T3), which coincides with mitotic inhibition of transcription. Ectopic expression of the H3T3 kinase haspin repressed TAF3-mediated transcription of endogenous and of reporter genes and decreased TFIID association with chromatin. Conversely, immunofluorescence and live-cell microscopy studies showed an increased association of TFIID with mitotic chromosomes upon haspin knockdown. Based on our observations, we propose that a histone H3 phospho-methyl switch regulates TFIID-mediated transcription during mitotic progression of the cell cycle.The EMBO Journal 12/2010; 29(23):3967-78. DOI:10.1038/emboj.2010.261 · 10.75 Impact Factor