Project description:Targeting of general coactivators, such as BRD4, is an emerging strategy to interfere with oncogenic transcription factors (TFs) in cancer. However, coactivator perturbations have the potential to influence the function of numerous TFs, thereby resulting in biological pleiotropy. Here we identify TAF12, an 18 kilodalton subunit of TFIID/SAGA coactivator complexes, as a selective requirement for acute myeloid leukemia (AML) progression. We trace this AML-specific dependency to a direct interaction between the TAF12/TAF4 histone-fold heterodimer and the transactivation domain of MYB, a TF with established roles in leukemogenesis. Ectopic expression of a histone-fold domain fragment of TAF4 can efficiently squelch TAF12 in cells, suppress MYB, and regress AML in mice. Our study reveals a strategy for potent MYB inhibition in AML and highlights how an oncogenic TF can be selectively neutralized by targeting a general coactivator complex.
Project description:Targeting of general coactivators, such as BRD4, is an emerging strategy to interfere with oncogenic transcription factors (TFs) in cancer. However, coactivator perturbations have the potential to influence the function of numerous TFs, thereby resulting in biological pleiotropy. Here we identify TAF12, an 18 kilodalton subunit of TFIID/SAGA coactivator complexes, as a selective requirement for acute myeloid leukemia (AML) progression. We trace this AML-specific dependency to a direct interaction between the TAF12/TAF4 histone-fold heterodimer and the transactivation domain of MYB, a TF with established roles in leukemogenesis. Ectopic expression of a histone-fold domain fragment of TAF4 can efficiently squelch TAF12 in cells, suppress MYB, and regress AML in mice. Our study reveals a strategy for potent MYB inhibition in AML and highlights how an oncogenic TF can be selectively neutralized by targeting a general coactivator complex.
Project description:TFIID and SAGA share a common set of TAFs, regulate chromatin, and deliver TBP to promoters. Here we examine their relationship within the context of the Saccharomyces cerevisiae genome-wide regulatory network. We find that while TFIID and SAGA make overlapping contributions to the expression of all genes, TFIID function predominates at ~90% and SAGA at ~10% of the measurable genome. Strikingly, SAGA-dominated genes are largely stress-induced and TAF-independent, and are down-regulated by the coordinate action of a variety of chromatin, TBP, and RNA polymerase II regulators. In contrast, the TFIID-dominated class is less regulated, but is highly dependent upon TAFs including those shared between TFIID and SAGA. These two distinct modes of transcription regulation might reflect the need to balance inducible stress responses with the steady output of housekeeping genes. Keywords = Taf1 Keywords = Spt3 Keywords = Gcn5
Project description:TFIID and SAGA share a common set of TAFs, regulate chromatin, and deliver TBP to promoters. Here we examine their relationship within the context of the Saccharomyces cerevisiae genome-wide regulatory network. We find that while TFIID and SAGA make overlapping contributions to the expression of all genes, TFIID function predominates at ~90% and SAGA at ~10% of the measurable genome. Strikingly, SAGA-dominated genes are largely stress-induced and TAF-independent, and are down-regulated by the coordinate action of a variety of chromatin, TBP, and RNA polymerase II regulators. In contrast, the TFIID-dominated class is less regulated, but is highly dependent upon TAFs including those shared between TFIID and SAGA. These two distinct modes of transcription regulation might reflect the need to balance inducible stress responses with the steady output of housekeeping genes. Keywords = Taf1 Keywords = Spt3 Keywords = Gcn5 Keywords: other
Project description:TFIID and SAGA are the only two known yeast complexes that modify chromatin and deliver TBP to promoters. Previous genome wide expression studies indicated that TFIID and SAGA positively regulate most but not all yeast genes. Using a relatively low noise microarray approach, we have re-examined the genome-wide dependence on TFIID and SAGA. We find that TFIID and SAGA contribute to the expression of virtually the entire genome, with TFIID being preferred at ~90% of the genes, and SAGA being preferred at ~10%. SAGA-dominated genes were found to overlap substantially with a previously described set of highly active genes that are attenuated in part by the TBP regulator NC2, and an auto-inhibitory function of TFIID. These SAGA-dominated genes also encompass most of the previously reported âTAF-independentâ genes. These results build upon and refine the generally held view that activators recruit either TFIID or SAGA to promoters which then bind and acetylate nucleosomes locally, thereby enhancing TBP delivery to the TATA box. Promoter-specific differences in the ability to alleviate auto-inhibitory activities associated with TFIID and SAGA might contribute to the preferential use one complex versus the other. Keywords = Chromatin Immunoprecipitation Keywords = genome-wide binding
Project description:Deletions within genes coding for subunits of the transcription coactivator SAGA caused strong genome-wide defects in transcription and SAGA-mediated chromatin modifications. In contrast, rapid SAGA depletion produced only modest transcription defects at 13% of protein-coding genes – genes that are generally more sensitive to rapid TFIID depletion. However, transcription of these “coactivator-redundant” genes is strongly affected by rapid depletion of both factors, showing the overlapping functions of TFIID and SAGA at this gene set. We suggest that this overlapping function is linked to TBP-DNA recruitment. The remaining 87% of expressed genes that we term “TFIID-dependent” are highly sensitive to rapid TFIID depletion and insensitive to rapid SAGA depletion. Genome-wide mapping of SAGA and TFIID found binding of both factors at many genes independent of gene class. DNA analysis suggests that the distinction between the gene classes is due to multiple components rather than any single regulatory factor or promoter sequence motif.
Project description:Deletions within genes coding for subunits of the transcription coactivator SAGA caused strong genome-wide defects in transcription and SAGA-mediated chromatin modifications. In contrast, rapid SAGA depletion produced only modest transcription defects at 13% of protein-coding genes – genes that are generally more sensitive to rapid TFIID depletion. However, transcription of these “coactivator-redundant” genes is strongly affected by rapid depletion of both factors, showing the overlapping functions of TFIID and SAGA at this gene set. We suggest that this overlapping function is linked to TBP-DNA recruitment. The remaining 87% of expressed genes that we term “TFIID-dependent” are highly sensitive to rapid TFIID depletion and insensitive to rapid SAGA depletion. Genome-wide mapping of SAGA and TFIID found binding of both factors at many genes independent of gene class. DNA analysis suggests that the distinction between the gene classes is due to multiple components rather than any single regulatory factor or promoter sequence motif.