THE YEAST SACCHAROMYCES-CEREVISIAE SYSTEM - A POWERFUL TOOL TO STUDY THE MECHANISM OF PROTEIN-SYNTHESIS INITIATION IN EUKARYOTES

This review summarizes recent progress in the study of initiation of protein synthesis in the yeast Saccharomyces cerevisiae. Biochemical and genetic approaches provide new insight into the recognition of the 5'-end of mRNA by initiation factors and 40S ribosomes, unwinding of mRNA secondary structures in the untranslated region and proper recognition of the AUG start codon. Experiments with initiation factor-dependent cell-free systems have facilitated studies of factor functions and factor requirements for translation of different mRNAs. The analysis of mutations which suppress the inhibitory effect on translation of RNA secondary structure in the 5'-untranslated region of yeast mRNAs has led to the identification of gene products which may be involved in both transcription and translation.