Organization and Expression of tRNA Genes in Saccharomyces cerevisiae

Abstract

INTRODUCTION Transfer RNAs have traditionally been among the favorite tools of molecular biologists. By virtue of their small size and relative abundance, tRNAs have long been the RNA molecules of choice for determination of primary, secondary, and tertiary structure. Their pivotal and multifaceted roles in cellular metabolism have made them the focus of biochemists’ attention for more than three decades; as a result, probably as much is known about their functional interactions as about any other class of macromolecules. The piece-de-resistance of their appeal stems from their amenability to genetic analysis. Once converted to a suppressor, a tRNA gene is no longer anonymous; its distinctive phenotype is readily identified and easily tracked. Given the appropriate genetic background, phenotypic loss of suppression can be used to identify each of the elements essential for transcription, maturation, and activity of the tRNA gene product. The power of these complementary approaches has already been amply demonstrated in both phage and bacterial systems. The ultimate goal of knowing not only the physical relationships among each of the nucleotides in the three-dimensional structure, but also of understanding how each of these structural features relates to the synthesis and function of the mature tRNA, is now conceivably within reach. As the details of this picture have become more refined, the need for comparable information in eukaryotes has become more apparent. Although contemporary methodology has now made it possible to rapidly accumulate primary sequence data from a variety of higher organisms, results of this kind are of only...