An ENU-induced point mutation in the mouse Btaf1 gene causes post-gastrulation embryonic lethality and protein instability
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE26743 | GEO | 2011/01/21
SECONDARY ACCESSION(S): PRJNA136329
REPOSITORIES: GEO
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Project description:The mouse Btaf1 gene, an ortholog of yeast MOT1, encodes a highly conserved general transcription factor. The function of this SNF-2 like ATPase has been studied mainly in yeast and human cells, which has revealed that it binds directly to TBP, forming the B-TFIID complex. This complex binds to core promoters of RNA polymerase II- transcribed genes and, of crucial importance, BTAF1-TBP interactions have been shown to affect the kinetics of TBP-promoter interactions. Here we report the isolation of a mouse line carrying a Btaf1 allele containing an ENU-induced point mutation that causes a substitution mutation in the BTAF1 ATPase domain. Embryos homozygous for this loss-of-function mutation appear to be morphologically normal until early somite stages, but die between embryonic day 9 and 10.5 displaying growth arrest and edema. Analyses in vitro suggest that the altered protein is less stable and, independent from this, functionally impaired in releasing of TBP from chromatin, but not in binding to TBP. A microarray screen for genes with altered expression in the Btaf V1330M mutant as compared to WT embryos was performed with RNA from whole embryos. We compared mRNA transcripts from pools of Btaf1-/- and Btaf1+/+ embryos. Where possible, we used 3-5-somite embryos, a stage we considered to be immediately prior to the emergence of a perceptible phenotype. The experiments were done in duplo, i.e. two sets of comparisons were made: in one case stage matching (i.e. number of somites counted) was the highest priority, in the other case the pools were designed such that a maximum number of litter mates were compared while a difference of up to five somites was allowed. cDNAs were synthesized and Cy-3/Cy-5 labeled cRNAs were generated by using a Low RNA Input Fluorescent Linear Amplification Kit (Agilent Technologies, Santa Clara, CA). The labeled cRNAs were hybridized on 4X44K Agilent Whole Mouse Genome Dual Color Microarrays (G4122F). Two dye-swap experiments were performed, resulting in four individual arrays. Microarray signal and background information were retrieved with Feature Extraction (V9.5.3, Agilent technologies). All data analyses were performed by using ArrayAssist (5.5.1, Stratagene Inc, La Jolla, CA) and Microsoft Excel (Microsoft Corporation, Redmont, WA). Genetic background: C57BL/6J were mutagenized, and crossed against FVB/NJ mice for positional mapping. The background of the mice used in the experiment is hybrid C57BL/6J *FVB/NJ with a percentage FVB between 50 and 90%.
2011-01-21 | E-GEOD-26743 | biostudies-arrayexpress
Project description:The Swi2/Snf2-family ATPase Mot1 displaces TBP from DNA in vitro, but the global relationship between Mot1 and TBP in vivo has been unclear. We therefore mapped the distribution of Mot1 and TBP on native chromatin at base-pair resolution. Mot1 and TBP binding sites coincide throughout the genome, and depletion of TBP results in a global decrease in Mot1 binding. Using midpoint-versus-length mapping to assess the spatial relationship of Mot1 and TBP on chromatin, we find evidence that Mot1 approaches TBP from the upstream direction, consistent with its in vitro mode of action. Strikingly, inactivation of Mot1 leads to both increases and decreases in TBP-genome association. Sites of TBP gain tend to contain robust TATA boxes, while sites of TBP loss contain poly(dA:dT) tracts that may contribute to nucleosome exclusion. We propose that the action of Mot1 is required to clear TBP from intrinsically preferred (TATA-containing) binding sites, ensuring sufficient soluble TBP to bind intrinsically disfavored (TATA-less) sites. We have analyzed the genomic distributions of yeast TBP and Mot1 using Occupied Regions of Genomes from Affinity-purified Naturally Isolated Chromatin and sequencing (ORGANIC-seq).
2013-10-21 | E-GEOD-44200 | biostudies-arrayexpress
Project description:The Swi2/Snf2-family ATPase Mot1 displaces TBP from DNA in vitro, but the global relationship between Mot1 and TBP in vivo has been unclear. We therefore mapped the distribution of Mot1 and TBP on native chromatin at base-pair resolution. Mot1 and TBP binding sites coincide throughout the genome, and depletion of TBP results in a global decrease in Mot1 binding. Using midpoint-versus-length mapping to assess the spatial relationship of Mot1 and TBP on chromatin, we find evidence that Mot1 approaches TBP from the upstream direction, consistent with its in vitro mode of action. Strikingly, inactivation of Mot1 leads to both increases and decreases in TBP-genome association. Sites of TBP gain tend to contain robust TATA boxes, while sites of TBP loss contain poly(dA:dT) tracts that may contribute to nucleosome exclusion. We propose that the action of Mot1 is required to clear TBP from intrinsically preferred (TATA-containing) binding sites, ensuring sufficient soluble TBP to bind intrinsically disfavored (TATA-less) sites.
2013-10-21 | GSE44200 | GEO
Project description:Mot1 is an essential TATA-binding protein (TBP)-associated factor and Snf2/Swi2 ATPase that both represses and activates transcription. Biochemical and structural results support a model in which ATP binding and hydrolysis induce a conformational change in Mot1 that drives local translocation along DNA, thus removing TBP. While this activity explains transcriptional repression, it does not as easily explain Mot1-mediated transcriptional activation, and several different models have been proposed to explain how Mot1 activates transcription. To better understand the function of Mot1 in yeast cells in vivo, particularly with regard to gene activation, TBP mutants were identified that bypass the requirement for Mot1 in vivo. Although TBP has been extensively mutated and analyzed previously, this screen uncovered two novel TBP variants that are unique in their ability to bypass the requirement for Mot1. Surprisingly, in vitro analyses reveal that rather than having acquired an improved biochemical activity, one of the TBPs was defective for interaction with Pol II preinitiation complex (PIC) components and other regulators of TBP function. The other mutant was defective for DNA binding in vitro, yet was still recruited to chromatin in vivo. These results suggest that Mot1-mediated dissociation of TBP (or TBP-containing complexes) from chromatin can explain the Mot1 activation mechanism at some promoters. The results also suggest that PICs can be dynamically unstable, and that appropriate PIC instability is critical for the regulation of transcription in vivo.
2008-12-17 | GSE12371 | GEO
Project description:The goal of the ChIP-seq study was to investigate the distribution of the TATA-binding protein (TBP) across the human genome. TBP is the DNA-binding subunit of the basal transcription factor TFIID for RNA polymerase II (pol II) and it also participates in other complexes for the other RNA polymerase. The BTAF1 ATPase forms a stable complex with TBP and regulates its activity in pol II transcription. BTAF1 is believed to mobilize TBP from promoter and non-promoter sites. To test this hypothesis, TBP ChIP samples were prepared from human HeLa cervix carcinoma cells after knock-down of BTAF1 expression and compared to HeLa cells with a control knock-down of GAPDH. GAPDH is a cytosolic enzyme that participates in glycolysis, and its inactivation is not expected to affect the genomic distribution of TBP, and acts as negative control. ChIP samples were sequenced using SOLiD technology along with the INPUT sample to normalize the distribution of background signals within each of the two chromatin samples.
2010-03-02 | GSE17937 | GEO
Project description:The goal of the ChIP-seq study was to investigate the distribution of the TATA-binding protein (TBP) across the human genome. TBP is the DNA-binding subunit of the basal transcription factor TFIID for RNA polymerase II (pol II) and it also participates in other complexes for the other RNA polymerase. The BTAF1 ATPase forms a stable complex with TBP and regulates its activity in pol II transcription. BTAF1 is believed to mobilize TBP from promoter and non-promoter sites. To test this hypothesis, TBP ChIP samples were prepared from human HeLa cervix carcinoma cells after knock-down of BTAF1 expression and compared to HeLa cells with a control knock-down of GAPDH. GAPDH is a cytosolic enzyme that participates in glycolysis, and its inactivation is not expected to affect the genomic distribution of TBP, and acts as negative control. ChIP samples were sequenced using SOLiD technology along with the INPUT sample to normalize the distribution of background signals within each of the two chromatin samples. 2 ChIP samples + one input sample
2010-03-02 | E-GEOD-17937 | biostudies-arrayexpress
Project description:TATA-binding protein (TBP) nucleates the assembly of the transcription preinitiation complex (PIC), and although TBP can bind promoters with high stability in vitro, recent results establish that virtually the entire TBP population is highly dynamic in yeast nuclei in vivo. This dynamic behavior is surprising in light of models which posit that a stable TBP-containing scaffold facilitates transcription reinitiation at active promoters. The dynamic behavior of TBP is a consequence of the enzymatic activity of the essential Snf2/Swi2 ATPase Mot1, suggesting that ensuring a highly mobile TBP population is critical for transcriptional regulation on a global scale. Here high-resolution tiling arrays were used to define how perturbed TBP dynamics impact the precision of RNA synthesis in Saccharomyces cerevisiae. We find that Mot1 plays a broad role in establishing the precision and efficiency of RNA synthesis: in mot1-42 cells, RNA length changes were observed for 713 genes, about twice the number observed in set2∆ cells, which display a previously reported propensity for spurious initiation within open reading frames. Loss of Mot1 led to both aberrant transcription initiation and termination, with prematurely terminated transcripts representing the largest class of events. Genetic and genomic analyses support the conclusion that these effects on RNA length are mechanistically tied to dynamic TBP occupancies at certain types of promoters. These results suggest a new model whereby dynamic disassembly of the PIC can influence productive RNA synthesis.
2010-09-08 | GSE18283 | GEO
Project description:Mot1 is a conserved and essential Swi2/Snf2 ATPase that can remove TATA-binding protein (TBP) from DNA using ATP hydrolysis, and in so doing exerts global effects on transcription. Spt16 is also essential and functions globally in transcriptional regulation as a component of the FACT histone chaperone complex. Here we demonstrate that Mot1 and Spt16 regulate a largely overlapping set of genes in Saccharomyces cerevisiae. As expected, Mot1 was found to control TBP levels at co-regulated promoters. In contrast, Spt16 did not affect TBP recruitment. Interestingly, Mot1 was required for Spt16 recruitment to co-activated promoters. In contrast, Spt16 levels in gene coding regions were unaffected by Mot1 as well as RNA polymerase II density. The co-localization of Mot1 and Spt16 at promoters and the broad overlap in the sets of genes they control is consistent with physical and genetic interactions between them. The data support a model in which these factors participate in a regulatory pathway in which Mot1 acts upstream of Spt16.
2016-05-16 | GSE72117 | GEO
Project description:Mot1 is a conserved and essential Swi2/Snf2 ATPase that can remove TATA-binding protein (TBP) from DNA using ATP hydrolysis, and in so doing exerts global effects on transcription. Spt16 is also essential and functions globally in transcriptional regulation as a component of the FACT histone chaperone complex. Here we demonstrate that Mot1 and Spt16 regulate a largely overlapping set of genes in Saccharomyces cerevisiae. As expected, Mot1 was found to control TBP levels at co-regulated promoters. In contrast, Spt16 did not affect TBP recruitment. On a global scale, Spt16 was required for Mot1 promoter localization, and Mot1 also affected Spt16 localization to genes. Interestingly, we find that Mot1 has an unanticipated role in establishing or maintaining the occupancy and positioning of nucleosomes at the 5’ ends of genes. Spt16 has a broad role in regulating chromatin organization in gene bodies, including those nucleosomes affected by Mot1. These results suggest that the large-scale overlap in Mot1 and Spt16 function arises from a combination of both their unique and shared functions in transcription complex assembly and chromatin structure regulation.
2016-05-16 | GSE80234 | GEO
Project description:Mot1 is a conserved and essential Swi2/Snf2 ATPase that can remove TATA-binding protein (TBP) from DNA using ATP hydrolysis, and in so doing exerts global effects on transcription. Spt16 is also essential and functions globally in transcriptional regulation as a component of the FACT histone chaperone complex. Here we demonstrate that Mot1 and Spt16 regulate a largely overlapping set of genes in Saccharomyces cerevisiae. As expected, Mot1 was found to control TBP levels at co-regulated promoters. In contrast, Spt16 did not affect TBP recruitment. On a global scale, Spt16 was required for Mot1 promoter localization, and Mot1 also affected Spt16 localization to genes. Interestingly, we find that Mot1 has an unanticipated role in establishing or maintaining the occupancy and positioning of nucleosomes at the 5â ends of genes. Spt16 has a broad role in regulating chromatin organization in gene bodies, including those nucleosomes affected by Mot1. These results suggest that the large-scale overlap in Mot1 and Spt16 function arises from a combination of both their unique and shared functions in transcription complex assembly and chromatin structure regulation. ChIP was performed for Spt16-myc in WT cells and mot1-42 cells in duplicate with input DNA from WT as control. ChIP was performed for Mot1-myc in WT cells and spt16-197 cells in dublicate with input DNA from WT as control. Micrococcal nuclease digested chromatin from WT, mot1-42, spt16-197, and mot1-42 spt16-197 cells were immunoprecipitated with H3 antibody in duplicate. All samples were sequenced by Illumina MiSeq.
2016-05-16 | E-GEOD-80234 | biostudies-arrayexpress