Polypeptide synthesis during protoplasmic incompatibility in the fungus Podospora anserina

In Podospora anserina, self-lysis resulting from the combination of the R and V incompatibility genes is accompanied by the appearance, in lysing cells, of specific enzyme activities, among which is a laccase exoenzyme, and by a quenching of ribonucleic acid synthesis. Present results show that the occurrence of the laccase is the result of de novo synthesis. By means of two-dimensional gel electrophoresis it was shown that the onset of self-lysis is accompanied by the immediate shut-off of more than 60% of the pre-existing normal polypeptide synthesis and the occurrence of at least 20 new polypeptides. The synthesis of these new polypeptides is active for several hours after the cessation of RNA synthesis, concurrently with the synthesis of about 30 normal polypeptides which is maintained. These modifications of protein synthesis are not accompanied by a concomitant variation in the level of polysomes. It is deduced that incompatibility genes are involved in the control of both transcription and translation.