earticle

영어

The high osmolarity glycerol (HOG) mitogen-activated protein kinase pathway plays important role in osmoadaptation in yeasts. We characterized the HOG1 homologue of the methylotrophic yeast Hansenula polymorpha. The amino acid sequence of HpHOG1 shows 70% of identity and 75% of similarity to that of S. cerevisiae Hog1. Deletion of Hphog1 gene caused the cell sensitive to high concentrations of NaCl and sorbitol. To understand the regulatory role of HpHOG1, transcriptome profiles of wild-type and Δhog1 mutant H. polymorpha strains challenged with 0.5 M NaCl for 30 min were analyzed. About 400 genes were differentially regulated in wild-type and Δhog1 mutant strain and the majority of them was involved in metabolism. Interestingly, many genes involved in the osmotic stress response, general stress response, and cell surface and cell wall formation were specifically up-regulated in wild-type strain. On the other hand, numerous genes involved in ribosomal protein synthesis were specifically down-regulated in Δhog1 mutant strain. Our results indicate that the osmotic stress response in H. polymorpha is modulated by the HOG1 MAP kinase pathway and other signal transduction mechanism.