Disease relevance of Fbl

• Effect of dexamethasone on nucleolar casein kinase II activity and phosphorylation of nucleolin in lymphosarcoma P1798 cells [1].
• Autoantibody to U3 nucleolar ribonucleoprotein (fibrillarin) in patients with systemic sclerosis [2].
• Interaction of the coronavirus nucleoprotein with nucleolar antigens and the host cell [3].
• Autoantibodies to nucleolar components are a common serological feature of patients suffering from scleroderma, a collagen vascular autoimmune disease [4].
• AbSMN immunostaining in neuroblastoma cells and mouse and human central nervous system (CNS) showed intense labeling of nuclear "gems," along with prominent nucleolar immunoreactivity in mouse and human CNS tissues [5].

Psychiatry related information on Fbl

• Since nuclear tau has also been found in neurons from patients with Alzheimer's disease (AD), aberrant nuclear tau could affect the nucleolar organization during the course of AD [6].

High impact information on Fbl

• In exploring the mechanism by which the active or silent state of rRNA genes is inherited, we found that NoRC, a nucleolar remodeling complex containing Snf2h (also called Smarca5, SWI/SNF-related matrix-associated actin-dependent regulator of chromatin, subfamily a, member 5), represses rDNA transcription [7].
• Transient transfection studies with PHF6 tagged with green fluorescent protein (GFP) showed diffuse nuclear staining with prominent nucleolar accumulation [8].
• Here, we demonstrate that two major nucleolar proteins, nucleolin and NO38, are highly phosphorylated during mitosis [9].
• These results identify two novel candidate substrates for cdc2 kinase, and they implicate protein phosphorylation in controlling mitotic changes in nucleolar structure and activity [9].
• Our unexpected results suggest a role for these major nucleolar proteins in the nucleocytoplasmic transport of ribosomal components [10].

Chemical compound and disease context of Fbl

• We compared modified to baseline B23 phosphoprotein distribution between predominantly nucleolar, mixed nucleolar-nuclear, or nuclear immunofluorescence using a monoclonal anti-B23 antibody in parental drug-sensitive and multidrug-resistant acute lymphatic leukemia and in daunorubicin-sensitive and -resistant murine hepatoma [11].
• OBJECTIVE: Autoantibodies to the U3 nucleolar ribonucleoprotein (RNP) fibrillarin occur in some patients with systemic sclerosis (SSc) or other connective tissue diseases and can be induced in certain mouse strains by injections of mercuric chloride, perhaps due to antigenic alteration of fibrillarin by mercury (Hg) [12].
• Changes in nucleolar number of ascites tumor cells treated with actinomycin D [13].
• In Ehrlich ascites tumour cell nuclei ledakrin (1-nitro-9/3'-dimethylpropyloamine/acridine-2 HCl) induces condensation and margination of chromatin, compaction and segregation of nucleolar components and conglomeration of chromatin granule clusters [14].
• Effects of dibutyryl cyclic adenosine monophosphate on nucleolar organizer regions and epidermal growth factor receptor of Dunn osteosarcoma cells [15].

Biological context of Fbl

• Implication of Nucleolar Protein SURF6 in Ribosome Biogenesis and Preimplantation Mouse Development [16].
• In this study, we examined the function of the evolutionary conserved nucleolar protein SURF6 in preimplantation mouse embryo development [16].
• Animals homozygous for the mutation were inviable, and massive apoptosis was observed in early Fibrillarin(-/-) embryos, showing that fibrillarin is essential for development [17].
• The latter observation might constitute the cell biological basis of autoimmune responses that specifically target fibrillarin in mercury-mouse models and scleroderma [18].
• The structure-function relationships of the nucleolar substructures were studied in preimplantation rabbit embryos, where nucleologenesis is extending over the first four cell cycles and may not be synchronous in each blastomere [19].

Anatomical context of Fbl

• Analysis of tissues and cell lines from mutant animals reveals the presence of extranucleolar foci that contain Fb and Nopp but not other typical nucleolar markers [20].
• Localization of fibrillarin and nucleolin in nucleoli of mouse preimplantation embryos [21].
• Accordingly, nucleoplasmic (snRNPs and SC-35) and nucleolar (fibrillarin) splicing factors are more abundant in hepatocyte nuclei of GM-fed than in control mice [22].
• Although both pre-coiled bodies and coiled bodies contain the nucleolar protein fibrillarin, the assembly of coiled bodies is separated both in time and in space from ribosome synthesis [23].
• The coiled body is an ubiquitous nuclear organelle that contains essential components of the pre-mRNA splicing machinery as well as the nucleolar protein fibrillarin [23].

Associations of Fbl with chemical compounds

• Nucleolin (713 aa), a major nucleolar protein, presents two structural domains: a N-terminus implicated in interaction with chromatin and a C-terminus containing four RNA-binding domains (RRMs) and a glycine/arginine-rich domain mainly involved in pre-rRNA packaging [24].
• Nucleolar casein kinase II activity and protein were also reduced (30-55% and 35-50% of control, respectively) by treatment with dexamethasone [1].
• NPI46 has two domains, a highly charged NH2 terminus similar to two other mammalian nucleolar proteins, nucleolin and Nopp140, and a COOH terminus with 45% homology to a family of mammalian and yeast proline isomerases [25].
• Insulin induces the serine phosphorylation of the nucleolar protein nucleolin at subnanomolar concentrations in differentiated 3T3-442A cells [26].
• After we treated hypophysectomized or oophorectomized rats with estrogen, which is known to increase nucleolar RMA synthesis in the fallopian tube and endometrium, nucleoli in the endothelial cells of the rat fallopian tube and uterus stained strongly for cGMP [27].

Other interactions of Fbl

• Determination of the functional domains involved in nucleolar targeting of nucleolin [24].
• Coilin and SMN complex members exhibit relatively long CB residence times, whereas components of snRNPs, small nucleolar RNPs, and factors shared with the nucleolus have significantly shorter residence times [28].
• Here, we show that the nucleolar localization of NDH II of murine 3T3 cells depended on an ongoing rRNA synthesis [29].
• Sequence determination of N-terminal 23 amino acid residues revealed that the MK-binding protein was nucleolin, a major nucleolar protein, which functions as a shuttle protein between the nucleus and cytoplasm and is located also on the cell surface [30].
• Distribution of nucleolar proteins B23 and nucleolin during mouse spermatogenesis [31].

Analytical, diagnostic and therapeutic context of Fbl

• Western blot analyses showed a reduction in fibrillarin protein levels in the heterozygous knockout animals [17].
• On the other hand, the immunofluorescent distribution of of nucleolin and p-103 (a nucleolar marker of the granular component) is compared to the ultrastructural distribution of the granular component analyzed by electron microscopy on oocytes of the same age [32].
• Molecular cloning and sequence analysis of U3 snoRNA-associated mouse fibrillarin [33].
• Immunocytochemistry revealed that fibrillarin and RNA polymerase I showed the same localisation in the nucleolar precursor bodies [34].
• Moreover, neither the localization of the two above proteins nor silver staining are unequivocally related to the nucleolar activity [35].

References