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Genetics. Jun 1986; 113(2): 229–246.
PMCID: PMC1202836

Genetic and Molecular Analysis of the GAL3 Gene in the Expression of the Galactose/Melibiose Regulon of SACCHAROMYCES CEREVISIAE

Abstract

During the galactose adaptation period of a Saccharomyces cerevisiae strain bearing a naturally occurring gal3 allele, we found a longer induction lag and slower rate of accumulation of GAL10 and MEL1 RNAs compared to wild-type strains. A strain of genotype gal3 gal1 gal7 is noninducible for MEL1 gene expression, but this expression block is bypassed by overexpression of the GAL4 gene or by deletion of the GAL80 gene, either of which causes a constitutive phenotype. An otherwise wild-type strain that bears a chromosomal gal3 gene disruption mutation does not produce wild-type GAL3 RNA and exhibits induction comparable to a strain bearing the naturally occurring gal3. Based on this array of results, we conclude that the GAL3 gene product executes its function at a point before GAL4 mediated transcription of the GAL1-10-7 and MEL1 genes. Thus, the data are consistent with the previously advanced hypothesis that the GAL3 gene product functions to synthesize the inducer or coinducer molecule. In experiments in which the presence of either the plasmid-carried cloned GAL3 gene or the plasmid-carried cloned GAL1-10-7 genes allows MEL1 induction of a gal3 gal1 gal7 cell, we find that loss of the plasmid results in the shutoff of MEL1 expression even when galactose is continuously present. Either GAL3 function or GAL1-10-7 functions are therefore required for both the initiation and the maintenance of the induced state. Since the strains bearing either the naturally occurring gal3 allele or the gal3 disruption (null) allele do induce, the plasmid loss experiments indicate the existence of two completely independent induction initiation-maintenance pathways, one requiring GAL3 function, the other requiring GAL1-10-7 function. Finally, Northern blot analysis reveals two major GAL3 transcripts that differ in size by approximately 500 nucleotides.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • Buckholz RG, Adams BG. Induction and genetics of two alpha-galactosidase activities in Saccharomyces cerevisiae. Mol Gen Genet. 1981;182(1):77–81. [PubMed]
  • Guyer MS. Uses of the transposon gamma delta in the analysis of cloned genes. Methods Enzymol. 1983;101:362–369. [PubMed]
  • Hawthorne DC, Mortimer RK. Chromosome Mapping in Saccharomyces: Centromere-Linked Genes. Genetics. 1960 Aug;45(8):1085–1110. [PMC free article] [PubMed]
  • Hinnen A, Hicks JB, Fink GR. Transformation of yeast. Proc Natl Acad Sci U S A. 1978 Apr;75(4):1929–1933. [PMC free article] [PubMed]
  • Ito H, Fukuda Y, Murata K, Kimura A. Transformation of intact yeast cells treated with alkali cations. J Bacteriol. 1983 Jan;153(1):163–168. [PMC free article] [PubMed]
  • Kew OM, Douglas HC. Genetic co-regulation of galactose and melibiose utilization in Saccharomyces. J Bacteriol. 1976 Jan;125(1):33–41. [PMC free article] [PubMed]
  • McLaughlin CS, Warner JR, Edmonds M, Nakazato H, Vaughan MH. Polyadenylic acid sequences in yeast messenger ribonucleic acid. J Biol Chem. 1973 Feb 25;248(4):1466–1471. [PubMed]
  • Mortimer RK, Hawthorne DC. Yeast genetics. Annu Rev Microbiol. 1966;20:151–168. [PubMed]
  • Reed J, Wintersberger E. Adenylic acid-rich sequences in messenger RNA from yeast polysomes. FEBS Lett. 1973 Jun 1;32(2):213–217. [PubMed]
  • Tsuyumu S, Adams BG. Population analysis of the deinduction kinetics of galactose long-term adaptation mutants of yeast. Proc Natl Acad Sci U S A. 1973 Mar;70(3):919–923. [PMC free article] [PubMed]

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