Protein synthesis in Aspergillus nidulans.

Abstract

In this review of protein synthesis, we have described a system for translation of mRNA using extracts of A. nidulans. This system is useful for characterizing mutants suspected to have defects in protein synthesis and for assessing the toxicity of various antibiotics and their effects on misreading the genetic code. The well developed genetical system of A. nidulans has enabled us to map at least 27 new genes whose mutation disturbs the level of translational accuracy. These mutants could be used to identify new components of translation or new roles for established components. The abundant fidelity mutations themselves could be used to elucidate the mechanism for maintaining the accuracy of protein synthesis. The large number of mutations in the control of fidelity indicate that mutations in other parts of the translation system could be easily obtained. This would be particularly important for initiation where many factors are thought to be needed and yet their exact roles are unknown. A. nidulans appears to have normal eukaryotic ribosomes and translation factors that can be used to study the mechanism of protein synthesis, its regulation, and the maintenance of its high fidelity. If highly purified factors were used, requirements for hitherto undiscovered factors could be seen. Since A. nidulans has typical eukaryotic responses to inhibitors of translation, it could be used to study new inhibitors, their mode of action, and their potency. Among the fungi, A. nidulans could be a worthy competitor to S. cerevisiae in the field of protein synthesis, particularly because so many translation genes have been identified. The system awaits further exploitation.