Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Keywords: CELLS ; CELL ; CELL-PROLIFERATION ; Germany ; GENERATION ; DISTINCT ; PROTEIN ; PROTEINS ; COMPONENTS ; MONOCLONAL-ANTIBODY ; BIOLOGY ; antibodies ; antibody ; PARTICLES ; IDENTIFICATION ; SPECTROMETRY ; REGION ; REGIONS ; XENOPUS ; MONOCLONAL-ANTIBODIES ; DNA-REPLICATION ; REPLICATION ; CLUSTER ; XENOPUS-LAEVIS ; WERNER-SYNDROME PROTEIN ; AMPLIFIED NUCLEOLI ; DESMOSOMAL PLAQUE ; NUCLEAR LAMINA PROTEINS ; NUCLEOPLASMIN FAMILY ; RIBOSOME BIOGENESIS
    Abstract: It has recently become clear that the nucleolus, the most prominent nuclear subcompartment, harbors diverse functions beyond its classic role in ribosome biogenesis. To gain insight into nucleolar functions, we have purified amplified nucleoli from Xenopus laevis oocytes using a novel approach involving fluorescence-activated cell sorting techniques. The resulting protein fraction was analyzed by mass spectrometry and used for the generation of monoclonal antibodies directed against nucleolar components. Here, we report the identification and molecular characterization of a novel, ubiquitous protein, which in most cell types appears to be a constitutive nucleolar component. Immunolocalization studies have revealed that this protein, termed NO66, is highly conserved during evolution and shows in most cells analyzed a dual localization pattern, i.e., a strong enrichment in the granular part of nucleoli and in distinct nucleoplasmic entities. Colocalizations with proteins Ki-67, HP1alpha, and PCNA, respectively, have further shown that the staining pattern of NO66 overlaps with certain clusters of late replicating chromatin. Biochemical experiments have revealed that protein NO66 cofractionates with large preribosomal particles but is absent from cytoplasmic ribosomes. We propose that in addition to its role in ribosome biogenesis protein NO66 has functions in the replication or remodeling of certain heterochromatic regions
    Type of Publication: Journal article published
    PubMed ID: 14742713
    Signatur Availability
    BibTip Others were also interested in ...
  • 2
  • 3
    Keywords: CELLS ; CELL-PROLIFERATION ; Germany ; PROTEIN ; PROTEINS ; transcription ; MOLECULAR CHARACTERIZATION ; DOMAIN ; SEQUENCE ; ACID ; antibodies ; antibody ; PARTICLES ; IDENTIFICATION ; mass spectrometry ; MASS-SPECTROMETRY ; C-MYC ; CONSTITUENTS ; compartmentalization ; POLYMERASE-I ; PROTEOMIC ANALYSIS ; MASSES ; SERUM ; molecular ; Xenopus laevis ; XENOPUS-LAEVIS ; assembly ; NUCLEOPLASMIN FAMILY ; RIBOSOME BIOGENESIS ; AMINO-ACID ; interaction ; nucleolus ; ribosome ; LAEVIS ; RIBONUCLEOPROTEIN COMPLEXES ; DNA HELICASE-II ; granular component ; MYC TARGET GENE ; PRE-RIBOSOMAL-RNA ; preribosomes ; protein NO66
    Abstract: The nucleolus is the most prominent intranuclear structure of almost all protein-synthesizing cells. It compromises a well-defined functional compartmentalization and a high complexity of molecular constituents. Here, we report on the identification and molecular characterization of a novel constitutive nucleolar component - protein N052 - that is present in diverse species from Xenopus laevis to human. The cDNA-deduced amino acid sequence of protein NO52 defines a polypeptide of a calculated mass of 52.8 kDa and an isoelectric point of 6.7. Inspection of the primary sequence disclosed that the protein contains a JmjC domain and is highly sequence-related to the recently described nucleolar protein NOW Immunolocalization studies revealed that protein NO52 is highly concentrated in the granular component of nucleoli and this characteristic intranuclear distribution is significantly affected by treatment of cells with (i) RNase A, (ii) actinomycin D and (iii) serum starvation. Interestingly, protein NO52 has been identified Lis a constituent of free preribosomal particles but is absent from cytoplasmic ribosomes. Analyses of immunocomplexes isolated from cellular extracts with an NO52-specific antibody by MALDI mass spectrometry further confirmed the interaction of protein NO52 with various ribosomal proteins as well as with a distinct set of non-ribosomal nucleolar proteins. The dependence of the nucleolar accumulation of the protein on ongoing rRNA transcription and the cellular metabolic state strongly suggest that protein NO52 is directly involved in ribosome biogenesis, most likely during the assembly process of preribosomal particles. (c) 2005 Elsevier GmbH. All rights reserved
    Type of Publication: Journal article published
    PubMed ID: 15819408
    Signatur Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...