Sequences within an upstream activation site in the yeast enolase gene ENO2 modulate repression of ENO2 expression in strains carrying a null mutation in the positive regulatory gene GCR1.
Transcription of the yeast enolase gene ENO2 is reduced 20- to 50-fold in strains carrying a null mutation in the positive regulatory gene GCR1. A small deletion mutation within one of two upstream activation sites (UAS elements) in the 5'-flanking region of ENO2 permitted wild-type levels of ENO2 gene expression in a strain carrying the gcr1 null mutation. These data show that sequences required for UAS element activity in GCR1 strains were required to repress ENO2 expression in a gcr1 strain. Protein factors that specifically bound to this UAS/repression site were identified. We show that the DNA-binding protein ABFI (autonomously replicating sequence-binding factor) is the major protein which binds the UAS/repression site. Minor DNA-binding activities that interact specifically with the UAS/repression site were also identified and may correspond to proteolytic breakdown products of ABFI. None of the observed binding activities were encoded by the GCR1 structural gene. A double-stranded oligonucleotide that included the UAS/repression site activated transcription of UAS-less ENO1 and ENO2 gene cassettes in vivo to wild-type levels in strains carrying the GCR1 allele as well as the gcr1 null mutation. These latter data show that the UAS/repression site is sufficient for transcriptional activation but is not sufficient to repress transcription of the enolase genes in a gcr1 genetic background.
Holland
J P
JP
Department of Biological Chemistry, School of Medicine, University of California, Davis 95616.
Brindle
P K
PK
Holland
M J
MJ
D001483:Base Sequence; D002872:Chromosome Deletion; D015342:DNA Probes; D004268:DNA-Binding Proteins / Q000378:metabolism; D004789:Enzyme Activation; D004794:Enzyme Repression; D005800:Genes, Fungal; D005809:Genes, Regulator; D008745:Methylation; D008969:Molecular Sequence Data; D009154:Mutation; D009710:Nucleotide Mapping; D010751:Phosphopyruvate Hydratase / Q000096:biosynthesis / Q000235:genetics* / Q000302:isolation & purification; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics*
D015342:DNA Probes; D004268:DNA-Binding Proteins; D010751:Phosphopyruvate Hydratase