title: A Gcn4p homolog is essential for the induction of a ribosomal protein L41 variant responsible for cycloheximide resistance in the yeast Candida maltosa.
abstract: Cycloheximide (CYH) resistance in the yeast Candida maltosa is based on the inducible expression of genes encoding a variant of ribosomal protein L41-Q, with glutamine at position 56 instead of the proline found in normal L41. The promoter of L41-Q2a, one of the L41-Q gene alleles encoding L41-Q, has an element similar to the Gcn4p-responsive element of Saccharomyces cerevisiae. In a previous study, this element was shown to be essential for the induction of L41-Q by CYH. In the present study, a C. maltosa GCN4 homolog, C-GCN4, was cloned. It had a long 5'-leader region with three upstream open reading frames. Enhanced expression of the C-GCN4 reporter fusion gene upon the addition of 3-aminotriazole or by mutations in start codons of all three upstream open reading frames indicates that C-GCN4 expression is under translation repression as was seen with GCN4. The C-GCN4-depleted mutant was unable to grow in a nutrient medium containing CYH and did not express L41-Q genes. Recombinant C-Gcn4p bound to the consensus DNA element for Gcn4p, 5'-(G/A)TGACTCAT-3', located upstream of L41-Q2a. Thus, C-Gcn4p, which likely functions in the general control of amino acid biosynthesis, is essential for the expression of L41-Q genes.
authors.affiliation: Department of Biotechnology, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Takaku
authors.forename: Eishun
authors.initials: E
authors.lastname: Mutoh
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Sagehashi
authors.forename: Ryouichi
authors.initials: R
authors.lastname: Fukuda
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Horiuchi
authors.forename: Kozo
authors.initials: K
authors.lastname: Ochi
authors.forename: Masamichi
authors.initials: M
authors.lastname: Takagi
authors.forename: Akinori
authors.initials: A
authors.lastname: Ohta
mesh_terms: D000935:Antifungal Agents / Q000494:pharmacology; D002175:Candida / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D003513:Cycloheximide / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D025141:Drug Resistance, Fungal / Q000235:genetics; D015966:Gene Expression Regulation, Fungal; D008969:Molecular Sequence Data; D011494:Protein Kinases / Q000235:genetics*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012269:Ribosomal Proteins / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics*; D014158:Transcription, Genetic
chemical_list: D000935:Antifungal Agents; D004268:DNA-Binding Proteins; C472563:RPL41 protein, S cerevisiae; D011994:Recombinant Proteins; D012269:Ribosomal Proteins; D029701:Saccharomyces cerevisiae Proteins; D003513:Cycloheximide; D011494:Protein Kinases