title: Isolation of a mutant allele that deregulates the threonine biosynthesis in Saccharomyces cerevisiae.
abstract: We have cloned the yeast allele HOM3-R2, that codes for a mutant aspartate kinase which is insensitive to feedback inhibition by threonine, by gap-repair. A strain carrying this allele in a multicopy plasmid, or integrated into the genome, accumulates 14-times and 8-times more threonine than the wild-type, respectively. The sequence of the mutant allele differs from that of the wild-type in a single base pair change, namely a G by an A, at position 1355 in the open reading frame. The fact that the presence of this mutant allele in a cell induces threonine overproduction points to aspartate kinase as the key enzyme in the regulation of threonine biosynthesis in yeast.
authors.affiliation: Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Spain.
authors.forename: E
authors.initials: E
authors.lastname: Martin-Rendon
authors.forename: M J
authors.initials: MJ
authors.lastname: Farfán
authors.forename: C
authors.initials: C
authors.lastname: Ramos
authors.forename: I L
authors.initials: IL
authors.lastname: Calderon
mesh_terms: D000483:Alleles; D001222:Aspartate Kinase / Q000096:biosynthesis / Q000235:genetics*; D003001:Cloning, Molecular; D005800:Genes, Fungal; D005838:Genotype; D016366:Open Reading Frames; D017354:Point Mutation; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism*; D013912:Threonine / Q000096:biosynthesis*
chemical_list: D013912:Threonine; D001222:Aspartate Kinase