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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Molecular and cellular biochemistry 191 (1999), S. 169-180 
    ISSN: 1573-4919
    Keywords: casein kinase II ; interferon ; NF-kappa B ; transcription ; phosphorylation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The Interferon Regulatory Factors (IRFS) play an important role in the transcriptional control of growth regulatory and immunoregulatory genes. The inducibility and availability of IRF-1 and IRF-2 are influenced by external stimuli, such as virus infection or interferon treatment. In the present study, we sought to examine the potential modulatory role of phosphorylation on IRF-1 transcriptional activity. During the purification of IRF recombinant proteins, a kinase activity copurified with IRF- 1 (and IRF-2) from baculovirus infected Sf9 insect cell extracts, but not from E. coli extracts. The kinase activity was also identified in Jurkat T cells, specifically interacted with IRF proteins in GST affinity chromatography, and phosphorylated IRF-1 with high specificity in vitro. Using an in gel kinase assay with recombinant IRF-1 as substrate, two molecular weight forms of the kinase (43 and 38 kDa) were identified. Biochemical criteria identified the kinase activity as the alpha catalytic subunit of casein kinase II (CKII). Furthermore, far western analysis of protein-protein interactions demonstrated that casein kinase II directly interacted with IRF-1 protein. Deletion mutation analysis of IRF-1 revealed that IRF-1 was phosphorylated at two clustered sites, one located between amino acids 138-150, the other in the C-terminal acidic activation domain between amino acids 219-231. Cotransfection studies comparing wild type and point mutated forms of IRF-1 demonstrated that mutations of the four phosphoaceptor residues in the C-terminal transactivation domain, significantly decreased transactivation by IRF-1, indicating that casein kinase II may be involved in the regulation of IRF-1 function. Strikingly, the casein kinase II clusters in IRF-1 resemble the sites identified in the C-terminal PEST domain of I〈κBα [29]. The present experiments, together with previously published studies with I〈κBα, c-Jun and other proteins, indicate a broad role for casein kinase II phosphorylation in the regulation of transcription factor activity.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 135 (1988), S. 324-331 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: To address the mechanisms that regulate expression of specific growth-related nuclear proto-oncogenes, the transcript levels of the c-fos, c-myc, (2′5′)-oligoadenylate synthetase, IFN-α1, and IFN-β1 genes have been measured in the human leukemic cell lines KG-1, U937, and HL-60 following growth stimulation by serum, induction of differentiation by tumor-promoting agents, and/or treatment of cells with exogenously supplied alpha interferon (rIFN-α2). Production of fos and myc RNA was measured by S1 mapping, using fos DNA probes which identified either primary unspliced transcripts or steady-state-spliced mRNA levels, and using a myc probe which spanned the two major c-myc start sites, P1 and P2. Pretreatment of a quiescent KG-1 cell population with IFN for 18 hours before serum addition decreased the stimulation of both fos and myc RNA production. In HL-60 and U937 cells, IFN pretreatment had no inhibitory effect on serum-induced fos or myc transcription; however, in U937, rIFN-α2 treatment alone stimulated fos mRNA 11-fold. Expression of 2′5′ oligoadenylate synthetase was induced in IFN-treated cultures but not in cells stimulated with serum alone. No serum-induced IFN-α1 or IFN-β1 gene expression was observed in KG-1 or U937 cells. These results demonstrate that exogenous rIFN-α2 treatment of quiescent KG-1 cells can antagonize the effect of growth factors by altering expression of nuclear proto-oncogenes, but in general growth inhibition is not obligatorily coupled to inhibition of proto-oncogene transcription.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 152 (1992), S. 10-18 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The NF-κB family of transcription proteins represents multiple DNA binding, rel related polypeptides that contribute to regulation of genes involved in immune responsiveness and inflammation, as well as activation of the HIV long terminal repeat. In this study multiple NF-κB related polypeptides ranging from 85 to 45 kDa were examined for their capacity to interact with the PRDII regulatory element of interferon β and were shown to possess distinct intrinsic DNA binding affinities for this NF-κB site and form multiple DNA binding homo- and heterodimer complexes in co-renaturation experiments. Furthermore, using DNA templates containing two copies of the PRDII domain linked to the rabbit β globin gene the purified polypeptides specifically stimulated NF-κB dependent transcription in an in vitro reconstitution assay as heterodimers but not as p50 homodimers. These experiments emphasize the role of NF-κB dimerization as a distinct level of transcriptional control that may permit functional diversification of a limited number of regulatory proteins. © 1992 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature structural & molecular biology 11 (2004), S. 1028-1030 
    ISSN: 1545-9985
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Medicine
    Notes: [Auszug] Infection by viral or bacterial pathogens is one of the great stresses in the life of a cell. How the invading pathogen is initially recognized and how the host cell responds within the first minutes to hours can dictate the subsequent development of immune protection, with far-reaching ...
    Type of Medium: Electronic Resource
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