Requirement for acidic amino acid residues immediately N-terminal to the conserved domain of Saccharomyces cerevisiae TFIID.

Abstract

TFIID binds to TATA boxes and initiates the assembly of general transcription factors and pol II on promoters. TFIID proteins from various species consist of a highly conserved carboxy terminal domain and very divergent amino terminal domains. We investigated the function of the non‐conserved amino terminal domain (residues 1–60) of Saccharomyces cerevisiae TFIID (YIID, 240 residues) by testing the ability of a series of YIID amino terminal deletion mutants to complement a YIID deficient yeast strain. Mutants with deletions up to amino acid 48 restored the YIID deficient yeast strain to an apparently wild type phenotype. However, deletion up to position 57 or 60 produced yeast strains which formed extremely small colonies. Moreover, overexpression of YIID delta 2–57 or YIID delta 3–60 protein in the presence of wild type YIID resulted in a dominant‐negative inhibition of growth. No difference between the basal transcriptional activity of wild type YIID and these amino terminal deletion mutants was observed in vitro. However, transcriptional activation in vivo of promoter‐lacZ fusions showed that the YIID delta 2–57 deletion affects the ability of certain promoters (CUP1 and an HSP UAS‐CYC1 promoter hybrid promoter) to respond to upstream factor stimulation. At least one inducible promoter, PHO5, was not affected by this deletion. The defect produced by YIID delta 2–57 was due to the deletion of several acidic residues present between residues 48 and 57. The results show that the conserved carboxy terminal domain of YIID is sufficient for cell viability. However, an acidic region just amino terminal to the conserved domain is required for normal growth and transcription control in most yeast strains.

Drosophila 230-kD TFIID subunit, a functional homolog of the human cell cycle gene product, negatively regulates DNA binding of the TATA box-binding subunit of TFIID.

“…The multimeric structure of TFIID is in striking contrast to its counterpart in yeast, which is purified as a single subunit (e.g., see Horikoshi et al 1989a). Consistent with this and despite the strong evolutionary conservation of the carboxy-terminal core of TFIIDx, the TFIIDr species from yeast to man differ in some aspects of function (Cormack et al 1991;Gill and Tjian 1991;Poon et al 1991;Zhou et al 1991;Berkenstam et al 1992). To test whether the capability for interaction with p230 was conserved, Drosophila p230 was probed with both human (Fig.…”

TBP, a universal eukaryotic transcription factor?

“…Furthermore, as summarized in Table 1, it is implicated in protein-protein interactions with the general transcription factors TFIIA and TFIIB, the yeast protein SPT3, and the trans-activators E1A, IE2, Zta, and probably VP16, as VP16 can interact with both human and yeast TBP (Stringer et al 1990;Ingles et al 1991). The TBP carboxy-terminal domain is also capable of restoring RNA polymerase III transcription in a heat-treated extract {White and Jackson 1992); and perhaps most striking, it is dispensable for viability in yeast (Cormack et al 1991;Gill and Tjian 1991;Reddy and Hahn 1991;Zhou et al 1991), although in some cases, the growth of yeast cells bearing only the carboxy-terminal domain of TBP was found to be severely impaired (Gill and Tjian 1991;Zhou et al 1991). Because the amino-terminal domain of TBP is not conserved, it is likely to interact with transcription factors that are species specific.…”

Factors (TAFs) required for activated transcription interact with TATA box-binding protein conserved core domain.

“…However, later molecular genetic studies in yeast revealed that the species-specific amino-terminal domain of yeast TBP is not required for viability (Cormack et al 1991;Gill and Tjian 1991;Reddy and Hahn 1991;Poon et al 1991;Zhou et al 1991). At first it seemed surprising that transcriptional activation might function through a different mechanism in yeast than in higher eukaryotes.…”