Inactivation of cleavage factor I components Rna14p and Rna15p induces sequestration of small nucleolar ribonucleoproteins at discrete sites in the nucleus.
Small nucleolar RNAs (snoRNAs) associate with specific proteins forming small nucleolar ribonucleoprotein (snoRNP) particles, which are essential for ribosome biogenesis. The snoRNAs are transcribed, processed, and assembled in snoRNPs in the nucleoplasm. Mature particles are then transported to the nucleolus. In yeast, 3'-end maturation of snoRNAs involves the activity of Rnt1p endonuclease and cleavage factor IA (CFIA). We report that after inhibition of CFIA components Rna14p and Rna15p, the snoRNP proteins Nop1p, Nop58p, and Gar1p delocalize from the nucleolus and accumulate in discrete nucleoplasmic foci. The U14 snoRNA, but not U3 snoRNA, similarly redistributes from the nucleolus to the nucleoplasmic foci. Simultaneous depletion of either Rna14p or Rna15p and the nuclear exosome component Rrp6p induces accumulation of poly(A)(+) RNA at the snoRNP-containing foci. We propose that the foci detected after CFIA inactivation correspond to quality control centers in the nucleoplasm.
Carneiro
Tiago
T
Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal.
Carvalho
Célia
C
Braga
José
J
Rino
José
J
Milligan
Laura
L
Tollervey
David
D
Carmo-Fonseca
Maria
M
D001483:Base Sequence; D002467:Cell Nucleus / Q000378:metabolism*; D005800:Genes, Fungal; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D017404:In Situ Hybridization, Fluorescence; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D012331:RNA, Fungal / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D020718:Ribonucleoproteins, Small Nucleolar / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D039221:mRNA Cleavage and Polyadenylation Factors / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism
C064793:NOP1 protein, S cerevisiae; D009687:Nuclear Proteins; D012331:RNA, Fungal; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D020718:Ribonucleoproteins, Small Nucleolar; D029701:Saccharomyces cerevisiae Proteins; D039221:mRNA Cleavage and Polyadenylation Factors; C512638:RNA14 protein, S cerevisiae; C512635:RNA15 protein, S cerevisiae; D049452:Green Fluorescent Proteins