YEAST EXPRESSION VECTORS USING RNA-POLYMERASE-III PROMOTERS

A series of Saccharomyces cerevisiae - Escherichia coli shuttle vector s is described in which small RNAs can be stably expressed in yeast fr om two different promoters for RNA polymerase III transcription. The v ectors are available in either high- or low-copy-number forms with eit her URA3, HIS3, or TRP1 selection markers, and are based on a previous ly described set of plasmid vectors [Sikorski and Hieter, Genetics 122 (1989) 19-27]. Transcripts have structured pre-tRNA or RPR1 leaders f used to RNA corresponding to inserted sequences. Levels of RNA accumul ation are dependent on plasmid copy number and the type of transcript.