title: A yeast mutant defective in the processing of 27S r-RNA precursor.
abstract: Among a group of 31 ts- yeast mutants screened electrophoretically for heat-sensitive synthesis of each stable RNA species, only mutant ts351 failed to accumulate 25S RNA at 36 degrees C. Pulse-labeling experiments at 36 degrees C showed that 35S and 27S precursors RNA and mature 18S r-RNA molecules are synthetized by ts351 cells but that 25S and 5.8S RNA species are not made and new 60S ribosomal sub-units are not assembled. The mutant is blocked at a specific point in r-RNA processing: the cutting of 27S to form 25S and 5.8S r-RNA.
mesh_terms: D004591:Electrophoresis, Polyacrylamide Gel; D005656:Fungal Proteins / Q000096:biosynthesis; D006358:Hot Temperature; D008970:Molecular Weight; D009154:Mutation; D009694:Nucleic Acid Precursors / Q000378:metabolism; D010641:Phenotype; D012335:RNA, Ribosomal / Q000032:analysis / Q000096:biosynthesis*; D012343:RNA, Transfer / Q000096:biosynthesis; D012441:Saccharomyces cerevisiae / Q000378:metabolism*
chemical_list: D005656:Fungal Proteins; D009694:Nucleic Acid Precursors; D012335:RNA, Ribosomal; D012343:RNA, Transfer