7 research outputs found
Inhibition by interferon of thymidine uptake and deoxyribonucleic acid synthesis in human lymphoblastoid cells
Changes in deoxynucleoside metabolism and DNA synthesis in interferon-treated human lymphoblastoid cells
Molecular Cloning of Two New Interferon-induced, Highly Related Nuclear Phosphoproteins
During the molecular cloning of the human dsRNA activated-p68 kinase (PKR), polyclonal antibodies against PKR selected, in addition to cDNAs corresponding to PKR, another cDNA presenting only slight homology with PKR cDNA. This cDNA recognized an mRNA species of 2 kilobases induced by both α- and γ- interferons. Its transcription did not require protein synthesis. On further library screening, it selected two highly related cDNAs, referred to as 75 and 41, displaying perfect homology over 612 base pairs and divergent at both ends. In addition, cDNA 75 presents an insertion of 150 base pairs highly homologous to a region common to both sequences. The 75 and 41 peptidic sequences are very hydrophilic, rich in basic amino acid residues, and contain several potential phosphorylation sites for different serine/threonine kinases. Furthermore, they present two protamine and histone-like nuclear targeting sequencaess well as some homology with helix-loop-helix motifs of some DNA-binding proteins. The 75-encoded product, which resolved as a 52-kDa protein after in vitro expression in rabbit reticulocyte lysates, was found to migrate as a 65-67-kDa protein after in vivo expression in insect cells. In accord with sequence data, this 65-67-kDa protein was found to be phosphorylated in vivo in the insect cells and was recovered from the membrane/nuclear pellet. In contrast, the 41-encodedproduct (30-kDa protein in reticulocyte lysates) could not be expressed in vivo, as it provoked a rapid and severe shutoff of protein synthesis in insect cells. The function of the 75 and 41 proteins and their relation to PKR remains to be determined. However, the presence of nuclear targeting sequences, phosphorylation sites, and helix-loop-helix motif is consistent with a role of these proteins in the mechanism of transduction of the interferon action
Enhanced expression of recombinant proteins in insect cells using a baculovirus vector containing a bacterial leader sequence
Interferon (ifn)-α2 genotype analysis of chinese chronic hepatitis b patients undergoing recombinant ifn-α2a therapy
Sixteen Chinese chronic hepatitis B virus (HBV)-infected patients were treated with recombinant interferon-α2a (rIFN-α2a). Of these, 8 made a response to IFN, with titers of neutralizing antibody of 141-4525 as determined by an antiviral neutralization bioassay. To determine whether the immunogenicity of the IFN was directly linked to the patients' genotype, their genomic DNA was analyzed for the presence of the human IFN-α2a gene. None of the patients possessed the gene for IFN-α2a, but only 50% developed neutralizing antibodies. The hypothesis, therefore, of a direct link between antibody formation and genotype cannot be sustained. Alternative explanations of the immunogenicity of IFN-α2a must be sought