ABSTRACT
The bovine papillomavirus type 1 (BPV-1) oncoprotein encoded by the E5 ORF is a small highly hydrophobic protein, which is capable of inducing oncogenic transformation of cells. We studied the effect of the BPV-1 E5 protein expression on the arachidonic acid metabolism in monkey (COS1) and human (C33A) cells. At relatively low protein concentrations the phospholipase A(2) (PLA(2)) activity and the arachidonic acid (AA) metabolism are activated. E5 mutant proteins, lacking cysteines responsible for the dimerisation of the protein (C37S, C37SC39S), and truncated E5, lacking the C-terminal region, are non-transforming and unable to stimulate the PLA(2) activity and AA metabolism. The transformation-defective mutant D33V, which does not activate the platelet-derived growth factor receptor (PDGFR), activates AA metabolism like wt E5. Our data suggest that the BPV-1 E5 protein could stimulate the AA metabolism independently of PDGF receptor.
Subject(s)
Arachidonic Acid/metabolism , Oncogene Proteins, Viral/metabolism , Phospholipases A/metabolism , Animals , COS Cells/metabolism , COS Cells/virology , Cell Transformation, Viral/physiology , Cells, Cultured , Enzyme Activation/physiology , Gene Expression/genetics , Humans , Mutagenesis, Site-Directed/genetics , Oncogene Proteins, Viral/genetics , Receptors, Platelet-Derived Growth Factor/metabolism , TransfectionABSTRACT
Current understanding of nuclear factor-kappaB (NF-kappaB) activation is derived mostly from in vitro studies, and in vivo human data are limited. This study provides first evidence showing that physical exercise (80% maximal O2 consumption, 1 h) may trigger NF-kappaB activation, as determined by electrophoretic mobility shift assay, in peripheral blood lymphocytes of physically fit young men. Supershift assay showed that the NF-kappaB protein complex contained the transcriptionally active p65 protein. Plasma levels of NF-kappaB-directed gene products such as tumor necrosis factor-alpha and interleukin-2 receptor confirmed that physical exercise caused NF-kappaB transactivation. Exercise-induced NF-kappaB activation in lymphocytes was associated with elevated levels of lipid peroxidation by-products in the plasma.
Subject(s)
Exercise , Lymphocytes/metabolism , NF-kappa B/blood , Adult , Humans , Lipid Peroxidation , Male , Receptors, Interleukin-2/blood , Time Factors , Transcription Factor RelA , Tumor Necrosis Factor-alpha/biosynthesisABSTRACT
Bovine papillomavirus type 1 (BPV-1) open reading frame E5 encodes the smallest known oncoprotein. This protein is involved in transforming cells during the early stage of infection. Nuclear factor kappa B (NF kappa B) is activated in the host cells as a result of different virus infections. It has been shown that reactive oxygen intermediates activate NF kappa B which leads the activation of several cellular genes. We studied the effect of BPV-1 ES protein on NF kappa B activation. We found that low and moderate concentrations of E5 protein activate NF kappa B. This activation is suppressed by superoxide dismutase. We conclude that the superoxide anion is involved in activation of NF kappa B.
Subject(s)
NF-kappa B/metabolism , Oncogene Proteins, Viral/metabolism , Protein-Tyrosine Kinases/metabolism , Superoxides/metabolism , Animals , Cattle , Genetic Vectors , Superoxide Dismutase/metabolismABSTRACT
Single functional human CuZnSOD gene encodes two species of mRNA differing in size by 200 nucleotides in the 3'-untranslated region (UTR). We studied the expression of the CuZnSOD cDNA with different 3'- and 5'-UTR. Deletion in the 5'-end does not affect the expression of the enzyme, however, deletion in the 3'-UTR decreases the level of expression of CuZnSOD. The plasmids containing the long CuZnSOD cDNA with all polyadenylation signal sequences utilize primarily the last polyadenylation site and give a long mRNA, which produces three times more enzyme than the short mRNA lacking the last polyadenylation site and the AU-rich region.
