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Mammalian H/ACA RNPs are essential for ribosome biogenesis, premessenger RNA splicing, and telomere maintenance. These RNPs consist of four core proteins and one RNA, but it is not known how they assemble. By interrogating the site of H/ACA RNA transcription, we dissected their biogenesis in single cells and delineated the role of the non-core protein NAF1(More)
Mammalian H/ACA small nucleolar RNAs and telomerase RNA share common sequence and secondary structure motifs that form ribonucleoprotein particles (RNPs) with the same four core proteins, NAP57 (also dyskerin or in yeast Cbf5p), GAR1, NHP2, and NOP10. The assembly and molecular interactions of the components of H/ACA RNPs are unknown. Using in vitro(More)
We report the identification and molecular characterization of a novel nucleolar protein of rat liver. As shown by coimmunoprecipitation this protein is associated with a previously identified nucleolar protein, Nopp140, in an apparently stoichiometric complex and has therefore been termed NAP57 (Nopp140-associated protein of 57 kD). Immunofluorescence and(More)
  • U T Meier
  • 1996
Rat Nopp140, a nonribosomal protein of the nucleolus and coiled bodies, was characterized as one of the most highly phosphorylated proteins in the cell. Based on its subcellular location, its nuclear localization signal binding capacity, and its shuttling between the nucleolus and the cytoplasm, Nopp140 was proposed to function as a chaperone in ribosome(More)
. The subcellular location of several nonribosomal nucleolar proteins was examined at various stages of mitosis in synchronized mammalian cell lines including HeLa, 3T3, COS-7 and HIV-1 Rev-expressing CMT3 cells. Nucleolar proteins B23, fibrillarin, nucleolin and p52 as well as U3 snoRNA were located partially in the peripheral regions of chromosomes from(More)
The H/ACA ribonucleoproteins (RNPs) are known as one of the two major classes of small nucleolar RNPs. They predominantly guide the site-directed pseudouridylation of target RNAs, such as ribosomal and spliceosomal small nuclear RNAs. In addition, they process ribosomal RNA and stabilize vertebrate telomerase RNA. Taken together, the function of H/ACA RNPs(More)
Cajal bodies (CBs) are subnuclear domains implicated in small nuclear ribonucleoprotein (snRNP) biogenesis. In most cell types, CBs coincide with nuclear gems, which contain the survival of motor neurons (SMN) complex, an essential snRNP assembly factor. Here, we analyze the exchange kinetics of multiple components of CBs and gems in living cells using(More)
Treacher Collins syndrome (TCS) is an autosomal dominant disorder of craniofacial development caused by mutations in the gene TCOF1. Its gene product, treacle, consists mainly of a central repeat domain, which shows it to be structurally related to the nucleolar phosphoprotein Nopp140. Treacle remains mostly uncharacterized to date. Herein we show that it,(More)
More than 100 mammalian H/ACA RNAs form an equal number of ribonucleoproteins (RNPs) by associating with the same four core proteins. The function of these H/ACA RNPs is essential for biogenesis of the ribosome, splicing of precursor mRNAs (pre-mRNAs), maintenance of telomeres and probably for additional cellular processes. Recent crystal structures of(More)