RESUMEN
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.
Asunto(s)
Ácido Araquidónico/metabolismo , Proteínas Oncogénicas Virales/metabolismo , Fosfolipasas A/metabolismo , Animales , Células COS/metabolismo , Células COS/virología , Transformación Celular Viral/fisiología , Células Cultivadas , Activación Enzimática/fisiología , Expresión Génica/genética , Humanos , Mutagénesis Sitio-Dirigida/genética , Proteínas Oncogénicas Virales/genética , Receptores del Factor de Crecimiento Derivado de Plaquetas/metabolismo , TransfecciónRESUMEN
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.
Asunto(s)
Regulación Enzimológica de la Expresión Génica/genética , ARN Mensajero/genética , Secuencias Reguladoras de Ácidos Nucleicos/genética , Superóxido Dismutasa/genética , Secuencia de Bases , Línea Celular , Clonación Molecular , ADN Complementario/genética , Vectores Genéticos/genética , Histiocitos/enzimología , Humanos , Datos de Secuencia Molecular , Poli A/biosíntesis , Poli A/genética , ARN Mensajero/biosíntesis , Secuencias Reguladoras de Ácidos Nucleicos/fisiología , Análisis de Secuencia de ADN , Eliminación de Secuencia/fisiología , Superóxido Dismutasa/biosíntesis , Superóxido Dismutasa/metabolismo , Transcripción Genética/genética , TransfecciónRESUMEN
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.
Asunto(s)
Ejercicio Físico , Linfocitos/metabolismo , FN-kappa B/sangre , Adulto , Humanos , Peroxidación de Lípido , Masculino , Receptores de Interleucina-2/sangre , Factores de Tiempo , Factor de Transcripción ReIA , Factor de Necrosis Tumoral alfa/biosíntesisRESUMEN
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.