hNaf1 is required for accumulation of human box H/ACA snoRNPs, scaRNPs, and telomerase.
The human telomerase ribonucleoprotein particle (RNP) shares with box H/ACA small Cajal body (sca)RNPs and small nucleolar (sno)RNPs the proteins dyskerin, hGar1, hNhp2, and hNop10. How dyskerin, hGar1, hNhp2, and hNop10 assemble with box H/ACA scaRNAs, snoRNAs, and the RNA component of telomerase (hTR) in vivo remains unknown. In yeast, Naf1p interacts with H/ACA snoRNP proteins and may promote assembly of Cbf5p (the yeast ortholog of dyskerin) with nascent pre-snoRNAs. Here we show that the human HsQ96HR8 protein, thereafter termed hNaf1, can functionally replace endogenous Naf1p in yeast. HeLa hNaf1 associates with dyskerin and hNop10 as well as box H/ACA scaRNAs, snoRNAs, and hTR. Reduction of hNaf1 steady-state levels by RNAi significantly lowers accumulation of these components of box H/ACA scaRNP, snoRNP, and telomerase. hNaf1 is found predominantly in numerous discrete foci in the nucleoplasm and fails to accumulate within Cajal bodies or nucleoli. Altogether, these results suggest that hNaf1 intervenes in early assembly steps of human box H/ACA RNPs, including telomerase.
Hoareau-Aveilla
Coralie
C
Equipe Labellisée Ligue Nationale contre le Cancer, Laboratoire de Biologie Moléculaire Eucaryote, UMR5099 CNRS-Université Paul Sabatier, Toulouse, France, European Union.
Bonoli
Mattia
M
Caizergues-Ferrer
Michele
M
Henry
Yves
Y
D015152:Blotting, Northern; D015153:Blotting, Western; D020541:Coiled Bodies / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D016650:Fluorescein-5-isothiocyanate; D019084:Fluorescent Antibody Technique, Indirect; D005456:Fluorescent Dyes; D005656:Fungal Proteins / Q000378:metabolism; D015870:Gene Expression; D006367:HeLa Cells; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007211:Indoles; D008856:Microscopy, Fluorescence; D009687:Nuclear Proteins / Q000378:metabolism; D010957:Plasmids / Q000235:genetics; D011233:Precipitin Tests; D034622:RNA Interference; D017411:Ribonucleoproteins, Small Nuclear / Q000096:biosynthesis*; D020718:Ribonucleoproteins, Small Nucleolar / Q000096:biosynthesis*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D019098:Telomerase / Q000096:biosynthesis*
D004268:DNA-Binding Proteins; D005456:Fluorescent Dyes; D005656:Fungal Proteins; D007211:Indoles; D009687:Nuclear Proteins; D017411:Ribonucleoproteins, Small Nuclear; D020718:Ribonucleoproteins, Small Nucleolar; D029701:Saccharomyces cerevisiae Proteins; C117046:TNIP1 protein, human; C007293:DAPI; D019098:Telomerase; D016650:Fluorescein-5-isothiocyanate