title: The requirement for the A block promoter element in tRNA gene transcription in vitro depends on the ionic environment.
abstract: When yeast cell extracts that faithfully transcribe class III genes are provided with different electrolyte ions, the pattern of transcripts changes. A transcription unit in pBR322, silent with 0.1M potassium chloride, becomes active in the presence of 0.1M potassium acetate. This pseudogene depends on transcription factors B and C and RNA polymerase III like a tRNA gene. The transcribed region contains the only sequence in pBR322 homologous to the modified B block consensus sequence GTTCRDNNC found in normal tRNA genes. The presence of a block A sequence is less evident. When a block A deleted tRNA(GLU) gene was constructed, it behaved similarly: poorly transcribed with 0.1M potassium chloride, well transcribed with 0.1M potassium acetate. In fact, the deletion of the A block promoter element from the tRNA(GLU) gene did not dramatically lower its transcription when tested with potassium acetate, while it had a strong negative effect when tested with potassium chloride. Consequently the requirement for this promoter element is not constant but is a function of the electrolyte composition.
authors.forename: O S
authors.initials: OS
authors.lastname: Gabrielsen
authors.forename: T B
authors.initials: TB
authors.lastname: Oyen
mesh_terms: D001483:Base Sequence; D003001:Cloning, Molecular; D004573:Electrolytes; D005800:Genes, Fungal; D005822:Genetic Vectors; D007477:Ions; D010957:Plasmids; D011401:Promoter Regions, Genetic; D012343:RNA, Transfer / Q000235:genetics*; D012346:RNA, Transfer, Amino Acyl / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D014158:Transcription, Genetic
chemical_list: D004573:Electrolytes; D007477:Ions; D012346:RNA, Transfer, Amino Acyl; D012343:RNA, Transfer