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.
Xiao
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Molecular Virology Section, Laboratory of Molecular Microbiology, NIAID, National Institutes of Health, Bethesda, Maryland 20892-0460, USA. hxiao@atlas.niaid.nih.gov
Jeang
K T
KT
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