Guided tours: from precursor snoRNA to functional snoRNP

Weinstein, Lara B.; Steitz, Joan A.

doi:10.1016/s0955-0674(99)80053-2

Cited by 268 publications

(190 citation statements)

References 5 publications

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“…The elevation of calgizzarin in colon carcinoma parallels our findings and indicates a role in squamous tumorigenesis (Tanaka et al, 1995). Another gene that was elevated in our study was the small nuclear RNA gene SM D1 which is important in the modification of ribosomal RNA and plays an important function in HNSC cell development Weinstein and Steitz, 1999). Previous studies of lung and oral squamous carcinoma Sueoka et al, 1999) have demonstrated the overexpression of that gene in the majority of those tumors and its absence in normal tissues.…”

Section: Discussionsupporting

confidence: 87%

Differential expression profiling of head and neck squamous carcinoma: significance in their phenotypic and biological classification

et al. 2002

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The genetic events associated with the development and progression of head and neck squamous carcinoma (HNSC) are largely unknown. We analysed 12 matched pairs of histologically normal squamous mucosa and tumor specimens from six conventional and six phenotypic variants HNSC to define the differentially expressed genes in these tumors. Parallel expression analysis of 8055 unique genes was performed, and the level of the hybridization signal for each gene was measured after normalization. Hierarchical cluster analysis of the expressed genes showed distinct interand intra-tumoral patterns in and between conventional squamous carcinoma and squamous carcinoma variants. We also identified 26 (0.32%) differentially expressed genes that were consistently different between matched pairs of normal and tumor specimens; a selected set of the overexpressed genes was validated using real-time quantitative RT -PCR. The majority of the genes were associated with differentiation and proliferation. Our study defines a set of genes that could form the basis for the construction of limited HNSC targeted expression array and indepth studies and further highlights gene profile differences that may be useful in pathobiologic classification of HNSC.

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Section: Discussionsupporting

confidence: 87%

Differential expression profiling of head and neck squamous carcinoma: significance in their phenotypic and biological classification

et al. 2002

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“…However, the molecular mechanisms governing the assembly of ribosomes and the majority of the nucleolar proteins involved in ribosome biogenesis are still ill defined. For instance, most of the ribonucleoproteins required for rRNA processing remain to be characterized (Weinstein and Steitz, 1999). Likewise, the mechanism by which mature ribosomal subunits are exported from nucleoli to the cytoplasm is not clearly elucidated (Aitchison and Rout, 2000;Kuersten et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

Functional Proteomic Analysis of Human Nucleolus

Scherl

Couté

Déon

et al. 2002

MBoC

445

378

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The notion of a “plurifunctional” nucleolus is now well established. However, molecular mechanisms underlying the biological processes occurring within this nuclear domain remain only partially understood. As a first step in elucidating these mechanisms we have carried out a proteomic analysis to draw up a list of proteins present within nucleoli of HeLa cells. This analysis allowed the identification of 213 different nucleolar proteins. This catalog complements that of the 271 proteins obtained recently by others, giving a total of ∼350 different nucleolar proteins. Functional classification of these proteins allowed outlining several biological processes taking place within nucleoli. Bioinformatic analyses permitted the assignment of hypothetical functions for 43 proteins for which no functional information is available. Notably, a role in ribosome biogenesis was proposed for 31 proteins. More generally, this functional classification reinforces the plurifunctional nature of nucleoli and provides convincing evidence that nucleoli may play a central role in the control of gene expression. Finally, this analysis supports the recent demonstration of a coupling of transcription and translation in higher eukaryotes.

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“…Besides the rRNA gene clusters and flanking sequences, nucleoli contain a large number of proteins and RNA components that are not part of mature cytoplasmic ribosomes but are involved in the transcriptional (Reeder, 1990;Paule, 1993) and post-transcriptional regulation of ribosome synthesis (Olson, 1990). Among these are small nucleolar RNAs (snoRNAs), which play a major role in the endo-and exonucleolytic processing of the large preribosomal precursor as well as in the specific modification of rRNA molecules by remodeling certain uridine residues into pseudouridines and by tagging ribose moieties with methyl groups (Tollervey, 1996;Tollervey and Kiss, 1997;Smith and Steitz, 1997;Weinstein and Steitz, 1999). A number of nonribosomal proteins that may be components of nucleolar structural elements, proteins that are transiently associated with preribosomes, and nucleocytoplasmic shuttle proteins have been identified, but only some of them were character-ized in detail (reviewed by Melese and Xue, 1995;Shaw and Jordan, 1995;Busch, 1997).…”

Section: Introductionmentioning

confidence: 99%

A Novel Helicase-Type Protein in the Nucleolus: Protein NOH61

Zirwes

Eilbracht

Kneissel

et al. 2000

MBoC

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We report the identification, cDNA cloning, and molecular characterization of a novel, constitutive nucleolar protein. The cDNA-deduced amino acid sequence of the human protein defines a polypeptide of a calculated mass of 61.5 kDa and an isoelectric point of 9.9. Inspection of the primary sequence disclosed that the protein is a member of the family of "DEAD-box" proteins, representing a subgroup of putative ATP-dependent RNA helicases. ATPase activity of the recombinant protein is evident and stimulated by a variety of polynucleotides tested. Immunolocalization studies revealed that protein NOH61 (nucleolar helicase of 61 kDa) is highly conserved during evolution and shows a strong accumulation in nucleoli. Biochemical experiments have shown that protein NOH61 synthesized in vitro sediments with ϳ11.5 S, i.e., apparently as homo-oligomeric structures. By contrast, sucrose gradient centrifugation analysis of cellular extracts obtained with buffers of elevated ionic strength (600 mM NaCl) revealed that the solubilized native protein sediments with ϳ4 S, suggestive of the monomeric form. Interestingly, protein NOH61 has also been identified as a specific constituent of free nucleoplasmic 65S preribosomal particles but is absent from cytoplasmic ribosomes. Treatment of cultured cells with 1) the transcription inhibitor actinomycin D and 2) RNase A results in a complete dissociation of NOH61 from nucleolar structures. The specific intracellular localization and its striking sequence homology to other known RNA helicases lead to the hypothesis that protein NOH61 might be involved in ribosome synthesis, most likely during the assembly process of the large (60S) ribosomal subunit. INTRODUCTIONNucleoli, the most conspicuous intranuclear structures in eukaryotic cells, are known to be the main site of ribosome biosynthesis (Hadjiolov, 1985;Scheer and Weisenberger, 1994;Scheer and Hock, 1999). More recently, however, it has also become clear that the nucleolus has additional functions and may be involved in the transport or assembly of various kinds of ribonucleoprotein particles (reviewed by Pederson, 1998).The production of preribosomal particles is a complex process, involving the transcription of the rRNA genes, the processing of the primary transcripts, and the addition of proteins to the nascent preribosomes as well as the incorporation of the 5S rRNA, which is synthesized outside of the nucleolus. Besides the rRNA gene clusters and flanking sequences, nucleoli contain a large number of proteins and RNA components that are not part of mature cytoplasmic ribosomes but are involved in the transcriptional (Reeder, 1990;Paule, 1993) and post-transcriptional regulation of ribosome synthesis (Olson, 1990). Among these are small nucleolar RNAs (snoRNAs), which play a major role in the endo-and exonucleolytic processing of the large preribosomal precursor as well as in the specific modification of rRNA molecules by remodeling certain uridine residues into pseudouridines and by tagging ribose moieties with methyl groups (To...

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Guided tours: from precursor snoRNA to functional snoRNP

Cited by 268 publications

References 5 publications

Differential expression profiling of head and neck squamous carcinoma: significance in their phenotypic and biological classification

Differential expression profiling of head and neck squamous carcinoma: significance in their phenotypic and biological classification

Functional Proteomic Analysis of Human Nucleolus

A Novel Helicase-Type Protein in the Nucleolus: Protein NOH61

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