Transcription and processing of intervening sequences in yeast tRNA genes

Abstract

Genes for yeast tRNA Tyr and tRNA Phe have been sequenced ( Goodman, Olson and Hall, 1977; Valenzuela et al., 1978) which contain additional nucleotides (intervening sequences) within the middle of the gene that are not present in the mature tRNA. We have isolated precursors to tRNA Tyr and tRNA Phe from a yeast temperature-sensitive mutant (at the rna1 locus) which accumulates only certain precursor tRNAs at the nonpermissive temperature. The tRNA Tyr and tRNA Phe precursors were analyzed by oligonucleotide mapping; they each contain the intervening sequence and fully matured 5′ and 3′ termini. Furthermore, these precursors were used as substrates to search for an enzymatic activity which can remove the intervening sequences and religate the ends. We have shown that wild-type yeast contains such an activity, and that this activity specifically removes the intervening sequences to produce mature-sized RNAs.