The Saccharomyces cerevisiae mevalonate diphosphate decarboxylase is essential for viability, and a single Leu-to-Pro mutation in a conserved sequence leads to thermosensitivity.
The mevalonate diphosphate decarboxylase is an enzyme which converts mevalonate diphosphate to isopentenyl diphosphate, the building block of isoprenoids. We used the Saccharomyces cerevisiae temperature-sensitive mutant defective for mevalonate diphosphate decarboxylase previously described (C. Chambon, V. Ladeveve, M. Servouse, L. Blanchard, C. Javelot, B. Vladescu, and F. Karst, Lipids 26:633-636, 1991) to characterize the mutated allele. We showed that a single change in a conserved amino acid accounts for the temperature-sensitive phenotype of the mutant. Complementation experiments were done both in the erg19-mutated background and in a strain in which the ERG19 gene, which was shown to be an essential gene for yeast, was disrupted. Epitope tagging of the wild-type mevalonate diphosphate decarboxylase allowed us to isolate the enzyme in an active form by a versatile one-step immunoprecipitation procedure. Furthermore, during the course of this study, we observed that a high level of expression of the wild-type ERG19 gene led to a lower sterol steady-state accumulation compared to that of a wild-type strain, suggesting that this enzyme may be a key enzyme in mevalonate pathway regulation.
Bergès
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T
Faculté des Sciences, Institut de Biologie Moléculaire et d'Ingénierie Génétique, Université de Poitiers, France. berges@hermes.univ-poitiers.fr
Guyonnet
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D
Karst
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F
D000483:Alleles; D002262:Carboxy-Lyases / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D017124:Conserved Sequence; D000939:Epitopes; D015870:Gene Expression; D005800:Genes, Fungal; D007930:Leucine / Q000378:metabolism; D008798:Mevalonic Acid / Q000378:metabolism; D017354:Point Mutation; D011392:Proline / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D013696:Temperature
D000939:Epitopes; D011392:Proline; D002262:Carboxy-Lyases; C022503:pyrophosphomevalonate decarboxylase; D007930:Leucine; D008798:Mevalonic Acid