title: Expression and inheritance of the yeast extrachromosomal element psi do not depend on RNA polymerase I.
abstract: The extrachromosomal element psi affects translation fidelity in the yeast Saccharomyces cerevisiae by increasing the efficiency of tRNA-mediated ochre suppression. The nature of the psi factor is unknown, although there is evidence that 3-microns circles from psi+ strains can be used to transform psi- cells to psi+. The 3-microns circles are extrachromosomal copies of the repeating ribosomal DNA unit, which is organized into two transcription units: the 35s rRNA precursor transcribed by RNA polymerase I, and the 5s rRNA transcribed by RNA polymerase III. We used a strain containing a mutation in RNA polymerase I to test whether psi expression and inheritance depended on RNA polI. Neither expression nor inheritance of psi requires intact RNA polI.
authors.affiliation: Department of Plant Sciences, Oxford University, UK.
authors.forename: C R
authors.initials: CR
authors.lastname: Nierras
authors.forename: B S
authors.initials: BS
authors.lastname: Cox
mesh_terms: D003433:Crosses, Genetic; D004271:DNA, Fungal / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D005111:Extrachromosomal Inheritance; D015870:Gene Expression; D005800:Genes, Fungal; D009154:Mutation; D014176:Protein Biosynthesis; D012318:RNA Polymerase I / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics*; D013172:Spores, Fungal / Q000235:genetics
chemical_list: D004271:DNA, Fungal; D004275:DNA, Ribosomal; D012318:RNA Polymerase I