Influence of the MTH genes on synthesis of alcohol oxidase and catalase in methylotrophic yeasts Pichia methanolica

摘要

In this study, we used two mutants of the methylotrophic Pichia methanolica which have lost the ability to assimilate methanol and with low level of alcohol oxidase activity (AOD) and their revertants to investigate the function of two genes: AUG2, which encodes one of AOD subunits and CTA1, a putative homolog of Saccharomyces cereviseae peroxisomal catalase (PCAT). Growing the mutants in conditions favorable for AUG2 expression (3% methanol-containing growth medium) resulted in increased expression of PCAT, whereas either carbon source free or 1% glycerol-containing growth media resulted in decreased expression of PCAT. The AOD isozyme pattern of the mth1 mutant gave a dominant isozyme band with electrophorectic mobility typical to isogenic form 9, the product of gene AUG2. Four spontaneous revertants of the mth1 mutant (Rmth1) were able to use methanol as the sole carbon source, and had increased activity of both AOD isozyme species 9 (the product of AUG2), and PCAT. These results confirmed the existence of regulatory elements in common that are likely to affect an expression of both AUG2 and CTA1 genes in the yeast P. methanolica.