Analysis of mutant tRNA gene transcripts in vivo in Saccharomyces cerevisiae by abortive primer extension

When the primer extension of a synthetic oligonucleotide hybridized to a complementary region of RNA is made in the presence of only three deoxyribonucleosides triphosphates, elongation of the primer stops as soon as the missing nucleotide is needed. This abortive primer extension assay has been adapted to analyse tRNA gene transcripts and has two main advantages. First it is specific and allows the identification of particular tRNA gene products in an homologous system provided the gene bears a point mutation. Second, it is highly sensitive and can be used to complement and confirm results of Northern blot hybridization. This assay should be a useful tool in the further in vivo study of the transcription and processing of particular tRNA genes in the homologous system. In this report the expression of wild-type and mutant yeast Sup4-0 tyrosine inserting suppressor gene was studied.