tRNA gene transcription in yeast: effects of specified base substitutions in the intragenic promoter

Abstract

The yeast SUP53 gene encodes a leucine-inserting amber suppressor tRNA. We have introduced specific base substitutions into both 5' and 3' elements of the intragenic promoter of this tRNA gene. The influence of these sequence changes on promoter function has been investigated by transcription of the mutant genes in a homologous cell-free system. Our results do not support the idea that tertiary intragenic structure is important in tRNA gene transcription. For one of the SUP53 mutants we are able to suggest a plausible molecular basis for defective transcription: a single base substitution in the 3' element of the intragenic promoter prevents the interaction of this element with a putative transcription factor.