Assembly of 5S ribosomal RNA is required at a specific step of the pre-rRNA processing pathway.
A collection of yeast strains surviving with mutant 5S RNA has been constructed. The mutant strains presented alterations of the nucleolar structure, with less granular component, and a delocalization of the 25S rRNA throughout the nucleoplasm. The 5S RNA mutations affected helix I and resulted in decreased amounts of stable 5S RNA and of the ribosomal 60S subunits. The shortage of 60S subunits was due to a specific defect in the processing of the 27SB precursor RNA that gives rise to the mature 25S and 5.8S rRNA. The processing rate of the 27SB pre-rRNA was specifically delayed, whereas the 27SA and 20S pre-rRNA were processed at a normal rate. The defect was partially corrected by increasing the amount of mutant 5S RNA. We propose that the 5S RNA is recruited by the pre-60S particle and that its recruitment is necessary for the efficient processing of the 27SB RNA precursor. Such a mechanism could ensure that all newly formed mature 60S subunits contain stoichiometric amounts of the three rRNA components.
Dechampesme
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AM
Service de Biochimie et de Génétique Moléculaire, Commissariat á L'Energie Atomique (CEA)/Saclay, F-91191 Gif-sur-Yvette Cedex, France.
Koroleva
O
O
Leger-Silvestre
I
I
Gas
N
N
Camier
S
S
D002466:Cell Nucleolus / Q000235:genetics / Q000378:metabolism; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism; D003593:Cytoplasm / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D005800:Genes, Fungal; D007700:Kinetics; D008970:Molecular Weight; D009154:Mutation; D009690:Nucleic Acid Conformation; D012322:RNA Precursors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012323:RNA Processing, Post-Transcriptional / Q000235:genetics*; D012331:RNA, Fungal / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012335:RNA, Ribosomal / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012341:RNA, Ribosomal, 5S / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D012269:Ribosomal Proteins / Q000235:genetics / Q000378:metabolism; D012270:Ribosomes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins
D005656:Fungal Proteins; C088396:LHP1 protein, S cerevisiae; D012322:RNA Precursors; D012331:RNA, Fungal; D012335:RNA, Ribosomal; D012341:RNA, Ribosomal, 5S; D016601:RNA-Binding Proteins; D012269:Ribosomal Proteins; D029701:Saccharomyces cerevisiae Proteins; C029742:ribosomal protein L5