Characterization of two genes encoding putative cysteine synthase required for cysteine biosynthesis in Schizosaccharomyces pombe.
Cysteine synthase catalyzes the formation of cysteine from O-acetylserine, and is the key enzyme for de novo cysteine biosynthesis in Schizosaccharomyces pombe. An examination of the S. pombe database revealed that two gene products are predicted to encode proteins homologous to eukaryotic cysteine synthases. Disruption of one of these candidates, cys1a+ (SPBC36.04), caused an obvious cysteine auxotrophy, while disruption of cys1b+ (SPAC3A12.17c) had no effect on the growth phenotype. Furthermore, overexpression of cys1b+ did not complement the cysteine auxotrophic phenotype of cys1a mutant cells. These results indicated that cys1a+, not cys1b+, primarily functions in the biosynthesis of cysteine in S. pombe cells. We constructed a bacterial-S. pombe shuttle vector containing cys1a+ as a selective marker gene. The combination of the cysteine auxotroph and new vector could be useful for the expression of a heterologous protein.
Department of Life Sciences, Faculty of Agriculture, Kagawa University, Ikenobe, Japan.
Yasuko
Y
Fujita
Kaoru
K
Takegawa
D000595:Amino Acid Sequence; D003470:Culture Media; D003545:Cysteine / Q000096:biosynthesis*; D003547:Cysteine Synthase / Q000235:genetics*; D017931:DNA Primers; D005800:Genes, Fungal / Q000235:genetics*; D005819:Genetic Markers; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D010641:Phenotype; D010957:Plasmids / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012568:Schizosaccharomyces / Q000235:genetics* / Q000378:metabolism / Q000648:ultrastructure; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics* / Q000378:metabolism
D003470:Culture Media; D017931:DNA Primers; D005819:Genetic Markers; D029702:Schizosaccharomyces pombe Proteins; D003547:Cysteine Synthase; D003545:Cysteine