Expression and processing of human ornithine-δ-aminotransferase in Saccharomyces cerevisiae

Kristiann M. Dougherty, Deborah A. Swanson, Lawrence C. Brody, David Valle

Research output: Contribution to journalArticle


Ornithine-δ-aminotransferase catalyzes the conversion of ornithine to glutamate-γ-semialdehyde. In humans, deficiency of this mitochondrial matrix enzyme results in the progressive blinding disorder, gyrate atrophy of the choroid and retina. To explore yeast as an expression system, we introduced a cDNA encoding human ornithine-δ-aminotransferase into an ornithine aminotransferase-deficient strain of Saccharomyces cerevisiae. The human enzyme was expressed at high levels, with activity 20-fold greater than that of wild-type yeast and 10-fold higher than in human fibroblasts. Although the normal location of ornithine-δ-aminotransferase in S.cerevisiae is cytosolic, human ornithine-δ-aminotransferase expressed in S.cerevisiae was localized to the mitochondrial matrix with correct proteolytic processing of its mitochondrial leader sequence. Despite this anomalous location in yeast, human ornithine-δ-aminotransferase complemented the phenotype of the mutant strain, restoring its ability to utilize ornithine as a sole nitrogen source. We also expressed a vitamin B6-responsive missense allele of ornithine-δ-aminotransferase (V332M) and showed that the biochemical phenotype of this allele is easily demonstrated confirming the usefulness of this system for examining mutations causing gyrate atrophy.

Original languageEnglish (US)
Pages (from-to)1835-1840
Number of pages6
JournalHuman Molecular Genetics
Issue number11
Publication statusPublished - Nov 1993


ASJC Scopus subject areas

  • Genetics
  • Statistics, Probability and Uncertainty
  • Applied Mathematics
  • Public Health, Environmental and Occupational Health
  • Molecular Biology
  • Genetics(clinical)

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