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Pop3p is essential for the activity of the RNase MRP and RNase P ribonucleoproteins in vivo
journal contribution
posted on 1997-01-15, 00:00 authored by Bernhard DichtlBernhard Dichtl, D TollerveyRNase MRP is a ribonucleoprotein (RNP) particle which is involved in the processing of pre-rRNA at site A3 in internal transcribed spacer 1. Although RNase MRP has been analysed functionally, the structure and composition of the particle are not well characterized. A genetic screen for mutants which are synthetically lethal (sl) with a temperature-sensitive (ts) mutation in the RNA component of RNase MRP (rrp2-1) identified an essential gene, POP3, which encodes a basic protein of 22.6 kDa predicted molecular weight. Overexpression of Pop3p fully suppresses the ts growth phenotype of the rrp2-1 allele at 34°C and gives partial suppression at 37°C. Depletion of Pop3p in vivo results in a phenotype characteristic of the loss of RNase MRP activity; A3 cleavage is inhibited, leading to under-accumulation of the short form of the 5.8S rRNA (5.8SS) and formation of an aberrant 5.8S rRNA precursor which is 5'-extended to site A2. Pop3p depletion also inhibits pre-tRNA processing; tRNA primary transcripts accumulate, as well as spliced but 5'- and 3'-unprocessed pre-tRNAs. The Pop3p depletion phenotype resembles those previously described for mutations in components of RNase MRP and RNase P (rrp2-1, rpr1-1 and pop1-1). Immunoprecipitation of epitope-tagged Pop3p co-precipitates the RNA components of both RNase MRP and RNase P. Pop3p is, therefore, a common component of both RNPs and is required for their enzymatic functions in vivo. The ubiquitous RNase P RNP, which has a single protein component in Bacteria and Archaea, requires at least two protein subunits for its function in eukaryotic cells.
History
Journal
EMBO journalVolume
16Issue
2Pagination
417 - 429Publisher
Nature Publishing GroupLocation
London, EnglandPublisher DOI
ISSN
0261-4189eISSN
1460-2075Language
engPublication classification
C1.1 Refereed article in a scholarly journalCopyright notice
1997, Nature Publishing GroupUsage metrics
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No categories selectedKeywords
POP3 geneRNA processingRNase MRPRNase PSaccharomyces cerevisiaeScience & TechnologyLife Sciences & BiomedicineBiochemistry & Molecular BiologyCell BiologyPRE-RIBOSOMAL-RNASACCHAROMYCES-CEREVISIAERIBONUCLEASE-PSCHIZOSACCHAROMYCES-POMBEPROTEIN-COMPONENTNUCLEAR GENEYEASTENDORIBONUCLEASEIDENTIFICATIONSITE
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