Response to leucine in Schizosaccharomyces pombe (fission yeast)

Leucine (Leu) is a branched-chain, essential amino acid in animals, including humans. Fungi, including the fission yeast Schizosaccharomyces pombe, can biosynthesize Leu, but deletion of any of the genes in this biosynthesis leads to Leu auxotrophy. In this yeast, although a mutation in the Leu biosynthetic pathway, leu1-32, is clearly inconvenient for this species, it has increased its usefulness as a model organism in laboratories worldwide. Leu auxotrophy produces intracellular responses and phenotypes different from those of the prototrophic strains, depending on the growing environment, which necessitates a certain degree of caution in the analysis and interpretation of the experimental results. Under amino acid starvation, the amino acid-auxotrophic yeast induces cellular responses, which are conserved in higher organisms without the ability of synthesizing amino acids. This mini-review focuses on the roles of Leu in S. pombe and discusses biosynthetic pathways, contribution to experimental convenience using a plasmid specific for Leu auxotrophic yeast, signaling pathways, and phenotypes caused by Leu starvation. An accurate understanding of the intracellular responses brought about by Leu auxotrophy can contribute to research in various fields using this model organism and to the understanding of intracellular responses in higher organisms that cannot synthesize Leu. This minireview summarizes the latest leucine metabolism mechanism and starvation response along with identification of a gene, ilv3+, involved in leucine synthesis in the fission yeast Schizosaccharomyces.

Automated summary

Leucine (Leu) is an essential branched-chain amino acid in animals, including humans. Although Leu auxotrophy is inconvenient for the fission yeast Schizosaccharomyces pombe, it has enhanced its usefulness as a model organism in laboratories. Leu auxotrophy induces intracellular responses and phenotypes different from those of the prototrophic strains, which necessitates caution in the analysis and interpretation of experimental results. Understanding the intracellular responses caused by Leu auxotrophy can contribute to the research using this model organism and to the understanding of intracellular responses in higher organisms. This minireview summarizes the latest research on leucine metabolism mechanism and starvation response in the fission yeast Schizosaccharomyces, along with the identification of the ilv3+ gene involved in leucine synthesis.