Schizosaccharomyces pombe Thiamine Pyrophosphokinase Is Encoded by Gene tnr3 and Is a Regulator of Thiamine Metabolism, Phosphate Metabolism, Mating, and Growth

Abstract

The Schizosaccharomyces pombe gene tnr3 has been genetically defined as a negative regulator of genes involved in thiamine metabolism (Schweingruber, A. M., Frankhauser, H., Dlugonski, J., Steinmann-Loss, C., and Schweingruber, M. E. (1992) Genetics 130, 445-449). We have isolated and sequenced the gene and show that it codes for a putative protein of 569 amino acids which exhibits, in its carboxyl-terminal half, good homology to Saccharomyces cerevisiae thiamine pyrophosphokinase (TPK). tnr3 mutants have reduced levels of intracellular thiamine diphosphate, show impaired TPK activity, which is enhanced by introducing the tnr3 wild type gene on a plasmid, and can be complemented by the S. cerevisiae TPK-encoding gene TH180. These data strongly suggest that tnr3 encodes S. pombe TPK. We present evidence that TPK also acts as a negative regulator for gene pho1, which is derepressed when cells are starved for phosphate and show that in contrast to wild type cells, tnr3 mutants mate constitutively in response to thiamine, indicating that TPK is also involved in regulation of mating. Disruption of the tnr3 gene is lethal, and a tnr3 mutant expressing only residual TPK activity grows slowly and shows aberrant morphology.

A metabolic strategy to enhance long-term survival by Phx1 through stationary phase-specific pyruvate decarboxylases in fission yeast

“…For this purpose, we monitored the mRNA levels of nmt1 + , nmt2 + , and bsu1 + genes along with the thi9 + gene, encoding a thiamine transporter [18], which is thiamine-repressible but not affected by Phx1. Transcripts from the tnr3 + gene encoding thiamine diphosphokinase [22], which is not repressible by thiamine, were monitored in parallel as a control.…”

Analysis of multidrug resistant group B streptococci with reduced penicillin susceptibility forming small, less hemolytic colonies

“…Moreover, because TPP, a coenzyme form of vitamin B1, is important for the formation of a coenzyme required for central metabolic functions (pyruvate decarboxylase, pyruvate dehydrogenase, α-ketoglutarate dehydrogenase, and transketolase), TPP might be essential for cell growth in bacteria and Δ tpk might exhibit growth defects [ 35 ]. Moreover, in Schizosaccharomyces pombe , tnr3 -recombinant strains (low-expressed TPK) grow slowly and show aberrant morphology [ 36 ]. The TPK deletion has not been detected in bacterial clinical isolates; therefore, these are the first known clinical isolates with the 276_277 ins G insertion in the tpk gene.…”

Isolation and characterization ofSaccharomyces cerevisiae mutants with derepressed thiamine gene expression

“…). As in the ®ssion yeast Schizosaccharomyces pombe, repression occurs when the intracellular TPP concentration reaches approximately twice its basal level, this being around 9 pmol/10 7 cells (Praekelt et al, 1994;Fankhauser et al, 1995). Mutations, e.g.…”