Activator-Specific Recruitment of TFIID and Regulation of Ribosomal Protein Genes in Yeast

Abstract

In yeast, TFIID strongly associates with nearly all ribosomal protein (RP) promoters, but a TAF-independent form of TBP preferentially associates with other active promoters. RP promoters are regulated in response to growth stimuli, in most cases by a Rap1-containing activator. This Rap1-dependent activator is necessary and sufficient for TFIID recruitment, whereas other activators do not efficiently recruit TFIID. TAFs are recruited to RP promoters even when TBP and other general transcription factors are not associated, suggesting that TFIID recruitment involves a direct activator-TAF interaction. Most RP promoters lack canonical TATA elements, and they are preferentially activated by the Rap1-containing activator. These results demonstrate activator-specific recruitment of TFIID in vivo, and they suggest that TFIID recruitment is important for coordinate expression of RP genes.

Compensation for differences in gene copy number among yeast ribosomal proteins is encoded within their promoters

“…In contrast, promoters with lower activities have, on average, Rap1 sites that are located ;60 bp further upstream compared with their location in the highactivity promoters, and are followed by a region with high nucleosome affinity. Rap1 is clearly critical for RP transcription, since deleting its sites ( Woudt et al 1986;Mencia et al 2002;Zhao et al 2006), and even changing the orientation of its sites (Woudt et al 1986) in RP promoters significantly reduces RP transcription. Our finding of different organizations of Rap1 sites between promoters with high and low activities further suggests that its contribution to transcription depends on its exact organization within the promoter, but it is unclear whether the effect depends on the exact location of the Rap1 site and/or on the presence of the nucleosome between the Rap1 site and the transcription start site.…”

The RNA polymerase II core promoter: a key component in the regulation of gene expression

“…These experiments indicate that a mechanism for enhancer-promoter specificity is the differential recruitment of TAFs by the enhancers. In related studies, it was found that a Rap1-containing activator recruits TFIID to ribosomal protein (RP) promoters, which generally lack canonical TATA box motifs (Mencía et al 2002). This Rap1-containing activator also stimulates transcription that is directed by the his3 T C element (which, as noted above, does not have a canonical TATA sequence) but not by the canonical T R TATA box.…”

Positive and negative functions of the SAGA complex mediated through interaction of Spt8 with TBP and the N-terminal domain of TFIIA

“…Only a small percentage of promoters seem to be exclusively SAGA-or TFIID-dependent in vivo (Lee et al 2000). In general, the requirement of a particular promoter for SAGA or TFIID is determined by the core promoter sequence, and the particular activator determines whether SAGA or TFIID is recruited to a promoter (Shen and Green 1997;Cheng et al 2002;Mencia et al 2002). It seems that many yeast promoters can use either SAGA or TFIID, because a double mutation of SAGA and TFIID subunits or a mutation of a shared TFIID/SAGA subunit affects expression from many more yeast genes than does a single mutation of either TFIID or SAGA specific subunits (Lee et al 2000).…”