THE STRUCTURE AND BIOGENESIS OF YEAST RIBOSOMES

This chapter reviews the recent progress in studies of the biogenesis and structure of yeast ribosomes, emphasizing results derived from experiments using classical and molecular genetics. Studies of the biosynthesis of the yeast ribosome offer an opportunity to investigate the coordinate expression of a moderately large set of genes that respond to the growth rate of the cell. To understand ribosome biosynthesis, one must concern the mechanisms responsible for the accumulation of ribosomal proteins in balance with each other and with rRNAs. The chapter also focuses on the structure and expression of ribosomal protein genes. The mechanisms of rRNA processing and ribosome assembly and the role of nucleolar molecules in these processes are only at their stage to be explored in eukaryotes. The signals that coordinate the transcription of these genes with all the three RNA polymerases have not been identified. By analogy to studies of mRNA processing, it should be possible to make effective use of rRNA-processing mutants or nucleolar protein or RNA mutants—in concern with a cell-free system—to define the pathway of processing in more detail and to determine the functions of trans-acting factors in this pathway. © 1991 Academic Press Inc.