Search results for "REcombinant protein"
showing 10 items of 707 documents
Oxidative stress inhibits IFN-α-induced antiviral gene expression by blocking the JAK–STAT pathway
2006
Abstract BACKGROUND/AIMS: Unresponsiveness to IFN-alpha is common in chronic hepatitis C. Since conditions associated with an increased oxidative stress (advanced age, steatosis, fibrosis, iron overload, and alcohol consumption) reduce the likelihood of response, we hypothesized that oxidative stress may affect the antiviral actions of IFN-alpha. METHODS: We examined in a human hepatocellular carcinoma cell line (Huh-7) the effect of hydrogen peroxide (H2O2), as a generator of oxidative stress, on the IFN-alpha signaling pathway. RESULTS: Pretreatment of Huh-7 cells with 0.5-1 mM H2O2 resulted in the suppression of the IFN-alpha-induced antiviral protein MxA and of IRF-9 mRNA expression. Th…
Expression analysis and functional activity of interleukin-7 splice variants.
2008
Alternative splicing results in multiple protein isoforms derived from a single gene. The magnitude of this process ranges from a complete loss of function to gain of new function. We examined, as a paradigm, alternative splicing of the non-redundant human cytokine, interleukin-7 (IL-7). We show that extensive IL-7 splicing in human tissues of different histology, including MTB+ granuloma lesions, transformed tissue and tumor cell lines. IL-7 splice variants were expressed as recombinant proteins. A differentially spliced IL-7 isoform, lacking exon 5, leads to STAT-5 phosphorylation in CD4+ and CD8+ T cells, promotes thymocyte maturation and T-cell survival. Human tumor lesions show aberran…
Structural stability and properties of three isoforms of the major light-harvesting chlorophyll a/b complexes of photosystem II.
2008
AbstractThree isoforms of the major light-harvesting chlorophyll (Chl) a/b complexs of photosystem II (LHCIIb) in the pea, namely, Lhcb1, Lhcb2, and Lhcb3, were obtained by overexpression of apoprotein in Escherichia coli and by successfully refolding these isoforms with thylakoid pigments in vitro. The sequences of the protein, pigment stoichiometries, spectroscopic characteristics, thermo- and photostabilities of different isoforms were analysed. Comparison of their spectroscopic properties and structural stabilities revealed that Lhcb3 differed strongly from Lhcb1 and Lhcb2 in both respects. It showed the lowest Qy transition energy, with its reddest absorption about 2 nm red-shifted, an…
Goodpasture antigen-binding protein, the kinase that phosphorylates the goodpasture antigen, is an alternatively spliced variant implicated in autoim…
2000
The non-collagenous C-terminal domain of the alpha(3) chain of collagen IV is the autoantigen in Goodpasture disease, an autoimmune disorder described only in humans. Specific N-terminal phosphorylation is a biological feature unique to the human domain when compared with other homologous domains lacking immunopathogenic potential. We have recently cloned from a HeLa-derived cDNA library a novel serine/threonine kinase (Goodpasture antigen-binding protein (GPBP)) that phosphorylates the N-terminal region of the human domain (Raya, A. Revert, F, Navarro, S. and Saus J. (1999) J. Biol. Chem. 274, 12642-12649). We show here that the pre-mRNA of GPBP is alternatively spliced in human tissues an…
The diversity of GABAA receptors. Pharmacological and electrophysiological properties of GABAA channel subtypes.
1998
The amino acid gamma-aminobutyric-acid (GABA) prevails in the CNS as an inhibitory neurotransmitter that mediates most of its effects through fast GABA-gated Cl(-)-channels (GABAAR). Molecular biology uncovered the complex subunit architecture of this receptor channel, in which a pentameric assembly derived from five of at least 17 mammalian subunits, grouped in the six classes alpha, beta, gamma, delta, sigma and epsilon, permits a vast number of putative receptor isoforms. The subunit composition of a particular receptor determines the specific effects of allosterical modulators of the GABAARs like benzodiazepines (BZs), barbiturates, steroids, some convulsants, polyvalent cations, and et…
Identification and cloning of odorant binding proteins from the scarab beetle Phyllopertha diversa.
1999
Abstract Wehave identified, cloned, and characterized two odorant binding proteins from the pale brown chafer, Phyllopertha diversa. One of the proteins (OBP1, 116 amino acids long) showed high amino acid identity (>90%) to two previously identified PBPs from scarab beetles. The second protein (OBP2) showed limited sequence similarity to lepidopteran and dipteran OBPs, but contained only 133 amino acids. Both proteins showed the occurrence of six highly conserved cysteines; electrospray mass spectral data suggested they are all bound in three disulfide bonds. During purification, OBP2 separated into several isoforms; N-terminal amino acid sequencing and electrospray ionization mass spectrom…
Purification and Characterization of the Soluble Interleukin-6 Receptor from Human Plasma and Identification of An Isoform Generated through Alternat…
1996
The soluble human interleukin-6 receptor (shIL6R) was purified from human plasma. In a single immunoaffinity purification step a 140000-fold enrichment with a yield of 95% was achieved. A subsequent IL-6 affinity chromatography resulted in a homogeneous receptor preparation but only in a yield of less than 5%. The biological activity of the soluble receptor was clearly demonstrated by its ability to induce the synthesis of the acute-phase protein α1-antichymotrypsin in HepG2 cells stably transfected with IL-6. Upon gel filtration, the native shIL6R showed an apparent molecular mass of 93 kDa. Analysis by SDS/PAGE revealed an apparent molecular mass of 65 kDa for the soluble receptor. Deglyc…
β1-Integrin Cytoplasmic Subdomains Involved in Dominant Negative Function
1998
The beta1-integrin cytoplasmic domain consists of a membrane proximal subdomain common to the four known isoforms ("common" region) and a distal subdomain specific for each isoform ("variable" region). To investigate in detail the role of these subdomains in integrin-dependent cellular functions, we used beta1A and beta1B isoforms as well as four mutants lacking the entire cytoplasmic domain (beta1TR), the variable region (beta1COM), or the common region (beta1 deltaCOM-B and beta1 deltaCOM-A). By expressing these constructs in Chinese hamster ovary and beta1 integrin-deficient GD25 cells (Wennerberg et al., J Cell Biol 132, 227-238, 1996), we show that beta1B, beta1COM, beta1 deltaCOM-B, a…
A Cre-inducible diphtheria toxin receptor mediates cell lineage ablation after toxin administration.
2004
A new system for lineage ablation is based on transgenic expression of a diphtheria toxin receptor (DTR) in mouse cells and application of diphtheria toxin (DT). To streamline this approach, we generated Cre-inducible DTR transgenic mice (iDTR) in which Cre-mediated excision of a STOP cassette renders cells sensitive to DT. We tested the iDTR strain by crossing to the T cell- and B cell-specific CD4-Cre and CD19-Cre strains, respectively, and observed efficient ablation of T and B cells after exposure to DT. In MOGi-Cre/iDTR double transgenic mice expressing Cre recombinase in oligodendrocytes, we observed myelin loss after intraperitoneal DT injections. Thus, DT crosses the blood-brain bar…
Spontaneous hepatic fibrosis in transgenic mice overexpressing PDGF-A.
2008
Platelet derived growth factor (PDGF) plays a central role in repair mechanisms after acute and chronic tissue damage. To further evaluate the role of PDGF-A in liver fibrogenesis in vivo, we generated transgenic mice with hepatocyte-specific overexpression of PDGF-A using the CRP-gene promoter. Transgenic but not wildtype mice showed expression of PDGF-A mRNA in the liver. Hepatic PDGF-A overexpression was accompanied by a significant increase in hepatic procollagen III mRNA expression as well as TGF-beta1 expression. Liver histology showed increased deposition of extracellular matrix in transgenic but not in wildtype mice. PDGF-A-transgenic mice showed positive sinusoidal staining for alp…