The effects of protein synthesis inhibition, and of mutations rna1.1 and rna82.1, on the synthesis of small RNAs in yeast

Abstract

Strains of Saccharomyces cerevisiae have been constructed that possess temperature-sensitive defects in tRNA precursor (pre-tRNA) splicing and which also lack the processing endonuclease that acts at the 3'-terminus of 5 S rRNA and 35 S rRNA precursors (pre-rRNAs). The unspliced pre-tRNAs accumulated by such strains at the nonpermissive temperature are identical in structure to those accumulated by pre-tRNA splicing-defective strains with a functional pre-5 S RNA processing enzyme. The pre-RNA processing activity is therefore not obligatorily involved in maturation of several yeast tRNAs. However, gels of the pulse-labelled RNAs of RNA82+ and rna82.1 strains provide evidence that this enzyme acts upon a few small unstable transcripts that are not 5 S RNA forms. The most prominent of these transcripts on gels was, in wild-type strains, an RNA 145 +/- 2 nucleotides in length.