Galactokinase encoded by GAL1 is a bifunctional protein required for induction of the GAL genes in Kluyveromyces lactis and is able to suppress the gal3 phenotype in Saccharomyces cerevisiae.
We have analyzed a GAL1 mutant (gal1-r strain) of the yeast Kluyveromyces lactis which lacks the induction of beta-galactosidase and the enzymes of the Leloir pathway in the presence of galactose. The data show that the K. lactis GAL1 gene product has, in addition to galactokinase activity, a function required for induction of the lactose system. This regulatory function is not dependent on galactokinase activity, as it is still present in a galactokinase-negative mutant (gal1-209). Complementation studies in Saccharomyces cervisiae show that K. lactis GAL1 and gal1-209, but not gal1-r, complement the gal3 mutation. We conclude that the regulatory function of GAL1 in K. lactis soon after induction is similar to the function of GAL3 in S. cerevisiae.
Meyer
J
J
Institut für Mikrobiologie, Heinrich-Heine-Universität, Düsseldorf, Germany.
Walker-Jonah
A
A
Hollenberg
C P
CP
D000483:Alleles; D000595:Amino Acid Sequence; D001483:Base Sequence; D004790:Enzyme Induction; D029968:Escherichia coli Proteins; D005686:Galactokinase / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D005690:Galactose / Q000494:pharmacology; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D005838:Genotype; D007716:Kluyveromyces / Q000187:drug effects / Q000201:enzymology / Q000235:genetics*; D026901:Membrane Transport Proteins / Q000096:biosynthesis; D008969:Molecular Sequence Data; D009004:Monosaccharide Transport Proteins; D016366:Open Reading Frames; D010641:Phenotype; D011994:Recombinant Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics*; D013489:Suppression, Genetic; D027981:Symporters; D001616:beta-Galactosidase / Q000096:biosynthesis
D029968:Escherichia coli Proteins; C050221:LacY protein, E coli; D026901:Membrane Transport Proteins; D009004:Monosaccharide Transport Proteins; D011994:Recombinant Proteins; D027981:Symporters; C021499:lactose permease; D005686:Galactokinase; D001616:beta-Galactosidase; D005690:Galactose