MUTANTS OF THE METHYLOTROPHIC YEAST HANSENULA-POLYMORPHA WITH IMPAIRED CATABOLITE REPRESSION

Mutants of the methylotrophic yeast Hansenula polymorpha resistant to 2-deoxyglucose during growth on methanol were isolated. Most of the mu tants had defects in the glucose catabolite repression of peroxisomal (alcohol oxidase and catalase) and cytosolic (formaldehyde dehydrogena se, formate dehydrogenase, dihydroxyacetone kinase, and fructose-1,6-d iphosphatase) enzymes of methanol oxidation and assimilation, as well as of the nonmethylotrophic enzyme alpha-glucosidase. When grown in me dia with glucose, mutant cells constitutively formed peroxisomes. The catabolite inactivation of alcohol oxidase by glucose was also impaire d in the mutants. All the mutations considered were recessive and rela ted to one gene, designated as GCR1 (glucose catabolite repression).