A multi-component upstream activation sequence of the Saccharomyces cerevisiae glyceraldehyde-3-phosphate dehydrogenase gene promoter

Summary The majority of the activation potential of the Saccharomyces cerevisiae TDH3 gene promoter is contained within nucleotides –676 to –381 (relative to the translation initiation codon). An upstream activation sequence (UAS) in this region has been characterized by in vitro and in vivo assays and demonstrated to be composed of two small, adjacent DNA sequence elements. The essential determinant of this upstream UAS is a general regulatory factor 1 (GRF1) binding site at nucleotides –513 to –501. A synthetic DNA element comprising this sequence, or an analogue in which two of the degenerate nucleotides of the GRF1 site consensus sequence were altered, activated 5 deleted TDH3 and CYC1 promoters. The second DNA element of the UAS is a 7 by sequence which is conserved in the promoters of several yeast genes encoding glycolytic enzymes and occurs at positions –486 to –480 of the TDH3 promoter. This DNA sequence represents a novel promoter element: it contains no UAS activity itself, yet potentiates the activity of a GRF1 UAS. The potentiation of the GRFl UAS by this element occurs when placed upstream from the TATA box of either the TDH3 or CYC1 promoters. The characteristics of this element (termed GPE for GRF1 site potentiator element) indicate that it represents a binding site for a different yeast protein which increases the promoter activation mediated by the GRF1 protein. Site-specific deletion and promoter reconstruction experiments suggest that the entire activation potential of the –676 to –381 region of the TDH3 gene promoter may be accounted for by a combination of the GRF1 site and the GPE.     

Preparation and use of a universal primed Sepharose for the purification of DNA-binding proteins

We have devised a novel method for the construction of a DNA affinity matrix and tested its use in the purification of a sequence-specific DNA-binding protein from the yeast Saccharomyces cerevisiae. The matrix was prepared in two steps: first, a palindromic oligonucleotide containing an XhoI cohesive end was covalently linked via its loop to a Sepharose matrix; second, directly to this 'universal' primed Sepharose was ligated a 37-bp oligonucleotide, with XhoI cohesive ends, containing the sequence of the upstream activation sequence 1 (UAS1) site of the yeast iso-1-cytochrome c (CYC1) gene. After fractionating a yeast crude extract through DEAE-cellulose, heparin ultrogel and Mono Q columns, a single pass through the affinity matrix allowed the purification to apparent homogeneity of the 120-kDa protein factor P, which is responsible for the binding to the UAS1 site.     

Yeast HAP1 activator binds to two upstream activation sites of different sequence

We show that the HAP1 protein binds in vitro to the upstream activation site (UAS) of the yeast CYC7 gene. Strikingly, this sequence bears no obvious similarity to the sequence bound by HAP1 at UAS1 of the CYC1 gene. The CYC1 and CYC7 sites compete for binding to HAP1 and have comparable affinities for the protein. The gross features of the interaction of HAP1 with the two sites are similar: multiple major and minor groove contacts, spanning 23 bp, on one helical face, with a back-side major groove contact toward one end. The precise positions of the contacts differ, however. A mutant form of HAP1, HAP1-18, abolishes the ability of the protein to bind to UAS1 but not CYC7 DNA. Possible mechanisms for how a single protein recognizes two sequences are discussed.     

The DAL7 promoter consists of multiple elements that cooperatively mediate regulation of the gene''s expression.

Expression of the allantoin system genes in Saccharomyces cerevisiae is induced by allophanate or its analog, oxalurate. This work provides evidence for the involvement of distinct types of cis-acting elements in the induction process. The first element was found to have the properties of an upstream activation sequence (UAS). This element was localized to a 16-base-pair (bp) DNA fragment containing a short 5-bp sequence that occurred repeatedly in the upstream region of DAL7. When present in two or more copies, the 16-bp fragment supported high-level beta-galactosidase production in a CYC1-lacZ expression vector; there was, however, no response to the allantoin pathway inducer. The second element had the properties of a negatively acting element or upstream repression sequence (URS). This element was localized to a 16-bp DNA fragment containing an 8-bp sequence that was repeated four times in the upstream region of DAL7. A fragment containing the 8-bp repeated sequence placed adjacent to the UAS-containing fragment mediated inhibition of the ability of the UAS to support lacZ expression regardless of whether inducer was present. A third element, designated an upstream induction sequence (UIS), was required for response to inducer. The UIS was localized to a small DNA fragment containing an approximately 10-bp sequence that was repeated twice in the upstream region of DAL7. When a fragment containing the 10-bp repeated sequence was placed adjacent to these UAS and URS elements, the construction (UIS-UAS-URS) supported normal oxalurate-mediated induction of beta-galactosidase synthesis. These data are consistent with the suggestion that multiple, cis-acting elements participate in the induction process.