Glutamine-rich domains activate transcription in yeast Saccharomyces cerevisiae.
Activation domains of eukaryotic transcription factors can be classified into at least three distinct types based on their amino acid composition: acidic, proline-rich, and glutamine-rich. Acidic activators, such as yeast GAL4 and GCN4 and herpes simplex virus VP16, have been shown to stimulate transcription in various higher and lower eukaryotic cells. Similarly, proline-rich activators also function in both mammalian and yeast cells. These activators are regarded to possess "universal" activating potentials. By contrast, several studies have suggested that glutamine-rich activators such as human Sp1 are active in higher (mammalian) but not lower (yeast) eukaryotic cells. One interpretation is that lower eukaryotic cells lack a critical co-factor necessary for a glutamine-rich domain. This reasoning is counter-intuitive because many native yeast activator proteins contain glutamine-rich domains. Here, we have investigated the activity of a glutamine-rich GAL4-Sp1 domain A (Sp1A) hybrid protein in yeast Saccharomyces cerevisiae. We show that GAL4-Sp1A activated a GAL1-lacZ reporter by more than 200-fold over basal when the reporter was carried on a 2mu vector. The generality of the Sp1A results is supported by our finding that yeast glutamine-rich domains from HAP2 and MCM1 are also transcriptionally active in S. cerevisiae. Interestingly, we found that glutamine-rich domains are considerably less potent when responsive promoters (i.e. GAL1-lacZ) are integrated into yeast chromosome. Thus our results segregate the inherent transcriptional activity of a glutamine-rich domain in yeast S. cerevisiae from its apparent lack of activity when assayed on chromosomally embedded promoters.
Molecular Virology Section, Laboratory of Molecular Microbiology, NIAID, National Institutes of Health, Bethesda, Maryland 20892-0460, USA. hxiao@atlas.niaid.nih.gov
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D023081:CCAAT-Binding Factor; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D005973:Glutamine; D026341:Minichromosome Maintenance 1 Protein; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D016329:Sp1 Transcription Factor / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
D023081:CCAAT-Binding Factor; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C052130:GAL4 protein, S cerevisiae; D026341:Minichromosome Maintenance 1 Protein; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D016329:Sp1 Transcription Factor; D014157:Transcription Factors; D005973:Glutamine