Pichia pastoris INO1 gene expression affects intracellular maltase activity and MAL1(+) gene expression in Schizosaccharomyces pombe

摘要

In our previous study, we found that the transfonnant Sch.p944 which contains the plasmid pADH-INO synthesized higher inositol than the transfonnant Sch.p1025 which contains the plasmid pSPIN-22. In this study, we examined the influence of 1N01 gene expression on intracellular maltase activity and MAL1(+) gene expression in these two transfonnants. The highest specific maltase activity was observed when Sch.p944 was grown in the synthetic medium containing initial 2.0% (w/v) glucose, whereas glucose repression of maltase activity occurred when Sch.p1025 was cultivated in the same medium containing glucose more than initial 0.5% (w/v), suggesting that synthesis of the maltase was derepressed in Sch.p944. Also, higher mRNA encoding intracellular maltase activity was found in Sch.p944 than that in Sch.p 1025 after 32 h of cell growth in the media containing initial 2.0% glucose, indicating that the derepression occurred at the transcriptional level. Furthermore, higher phosphatidylinositol (PI) content was detected in Sch.p944 cells grown in the medium containing initial 2.0% (w/v) glucose for 32 h than in Sch.p1025 cells grown under the sane conditions, inclicating that PI might be involved in derepression of MAL1(+) gene expression and intracellular maltase activity.