PEROXISOMAL REMNANTS IN PEROXISOME-DEFICIENT MUTANTS OF THE YEAST HANSENULA-POLYMORPHA

We have analyzed the presence of peroxisomal remnants ('ghosts') in th ree peroxisome-deficient (per) mutants of the yeast Hansenula polymorp ha, namely Delta per4, Delta per5 and Delta per10. Under peroxisome-in ducing growth conditions peroxisomal membrane proteins (PMPs) mere nor mally synthesized in cells of these mutants. In addition, these cells contained clusters of small membranous vesicles, which were absent in cells grown under peroxisome-repressing growth conditions. These struc tures displayed typical peroxisomal properties in that they proliferat ed upon overproduction of Per8p, the H. polymorpha peroxisome prolifer ation factor. Moreover, in Delta per4 and Delta per5 these vesicles we re susceptible to glucose-induced proteolytic degradation.