Holo-TFIID controls the magnitude of a transcription burst and fine-tuning of transcription

Abstract

Transcription factor (TF)IID is a central player in activated transcription initiation. Recent evidence suggests that the role and composition of TFIID are more diverse than previously understood. To investigate the effects of changing the composition of TFIID in a simple system, we depleted TATA box-binding protein-associated factor (TAF)1 from Drosophila cells and determined the consequences on metal-induced transcription at an inducible gene, metallothionein B. We observe a marked increase in the levels of both the mature message and pre-mRNA in TAF1-depleted cells. Under conditions of continued metal exposure, we show that TAF1 depletion increases the magnitude of the initial transcription burst but has no effect on the timing of that burst. We also show that TAF1 depletion causes delay in the shutoff of transcription upon removal of the stimulus. Thus, TAFs are involved in both establishing an upper limit of transcription during induction and efficiently turning the gene off once the inducer is removed. Using genome-wide nascent sequencing, we identify hundreds of genes that are controlled in a similar manner, indicating that the findings at this inducible gene are likely generalizable to a large set of promoters. There is a long-standing appreciation for the importance of the spatial and temporal control of transcription. Here we uncover an important third dimension of control: the magnitude of the response. Our results show that the magnitude of the transcriptional response to the same signaling event, even at the same promoter, can vary greatly depending on the composition of the TFIID complex in the cell.heavy metal | MtnA | coactivator | RNA polymerase

Structural and functional insight into TAF1–TAF7, a subcomplex of transcription factor II D

“…Substitution of evolutionary conserved yTAF1 Phe493, His494, Phe480 residues, and yTAF7 Phe186 with Ala (Fig. 3D) permitted stable yTAF1/7 formation but completely abolished binding to H3K27me3 (19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35) peptide (Table S2). Other targeted mutations disrupted stable yTAF1/7 complex formation (Table S2).…”

Mot1 Redistributes TBP from TATA-Containing to TATA-Less Promoters

“…In vivo support for this structural model derives from the observation that TAF1 is highly enriched at TATA-less promoters but depleted from TATA-containing promoters in yeast (29). Furthermore, depletion of yeast TAF1 results in increased TBP mobility (51), and TAF1 depletion in Drosophila cells leads to dissociation of TBP from TFIID (52,53) as well as increases in nascent RNA production from TATA-containing promoters (52). As TATA-less promoters are likely to be lower-affinity sites for TBP binding, the protection of TBP from Mot1-mediated dissociation by TAF1 may serve to ensure that sufficient TBP remains associated with these promoters for appropriate transcriptional activation.…”

The Metazoan-Specific Mediator Subunit 26 (Med26) Is Essential for Viability and Is Found at both Active Genes and Pericentric Heterochromatin in Drosophila melanogaster

“…Cells were then cross-linked with 1.5% formaldehyde. Nuclei were isolated and lysed, and chromatin was sonicated to 500 to 1,000 bp in length as described previously (29). Chromatin was diluted and incubated with rabbit polyclonal sera against Med26 overnight.…”