Mutation thi81 causing a deficiency in the signal transduction of thiamine pyrophosphate in Saccharomyces cerevisiae.
We isolated a strain carrying a recessive constitutive mutation (thi81) for the expression of thiamine metabolism in Saccharomyces cerevisiae. The thi81 mutant exhibits significant thiamine transport, thiamine-repressible acid phosphatase (T-rAPase) activities and significant activities of enzymes involved in thiamine biosynthesis which are repressed in the wild-type strain in medium supplemented with thiamine (2 x 10(-7) M). The thi81 mutant exhibited the same level of thiamine pyrophosphokinase activity and intracellular thiamine pyrophosphate concentration as the wild-type strain in medium supplemented with exogenous thiamine. The mutant strain constitutively produced PHO3 mRNA encoding T-rAPase in medium supplemented with thiamine. These results suggest that the thi81 mutant lacks a negative factor involved in the regulation of the genes encoding proteins involved in yeast thiamine metabolism.
Nishimura
H
H
Department of Biochemistry, Kyoto Prefectural University of Medicine, Japan. hiroshin@basic.kpu-m.ac.jp
Kawasaki
Y
Y
Nosaka
K
K
Kaneko
Y
Y
D000135:Acid Phosphatase / Q000378:metabolism; D003470:Culture Media; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D009154:Mutation; D010641:Phenotype; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000201:enzymology / Q000235:genetics*; D015398:Signal Transduction / Q000502:physiology*; D013831:Thiamine / Q000378:metabolism / Q000494:pharmacology; D013835:Thiamine Pyrophosphate / Q000032:analysis / Q000502:physiology*
D003470:Culture Media; D005656:Fungal Proteins; D000135:Acid Phosphatase; D013835:Thiamine Pyrophosphate; D013831:Thiamine