Analysis of the genome-wide gene expression of heterologous protein producing fission yeast strains.
Hideki Tohda, Hiromichi Kumagai, Yuko Giga-Hama
ASPEX Division, Asahi Glass Co., Ltd., Kanagawa-ku, Yokohama, 221-8755, Japan
Fission yeast Schizosaccharomyces pombe ( S. pombe ) has been regarded as a useful host for the heterologous protein production, however, the protein biosynthesis mechanism has not been well studied and genes related to heterologous protein production are still unknown. To find out the genes related to the stress response in the heterologous protein over production, we developed a whole-genome 70-mer nucleotide-based DNA microarray. Analysis of both wild-type and foreign gene expression cassette containing strain was performed to identify transcripts whose levels affected by the heterologous protein production. Surprisingly, there is no significant difference between wild-type and human lipocortin I producing strain, even this protein was produced at a high level. Similar results were also shown in 10 strains producing independent heterologous protein at levels of 30-50% of total cellular protein or 100-300mg/l of culture medium, suggesting that the heterologous protein produced at high levels does not have a considerable impact on transcriptome. In the case of proteins with difficult to produce at high levels, hundreds of genes were up-regulated including molecular chaperons, but there is no obvious up-regulation of protease genes. These findings are useful information for the improvement of heterologous protein production system. Part of this work was supported by the minimum genome factory project conducted by NEDO, Japan.