Induction of c-jun protooncogene expression and transcription factor AP-1 activity by the polyoma virus middle-sized tumor antigen.

AUTOR(ES)

Schönthal, A

RESUMO

Polyoma virus middle-sized tumor (PymT) antigen is required for neoplastic cell transformation by polyoma virus. We studied changes in gene expression accompanying expression of PymT in murine fibroblasts. These experiments showed that PymT differentially affects several growth-related genes. c-jun protooncogene expression was highly increased, whereas the expression of two growth arrest-specific genes (gas) was reduced, in cells transformed by PymT. Cotransfection experiments showed that the increase in c-jun expression resulted from elevated activity of the transcription factor AP-1 and was mediated through the phorbol 12-tetradecanoate 13-acetate response element in the c-jun promoter. The degree of c-Jun/AP-1 activation by different PymT mutants correlated with their transforming capability, suggesting that regulation of c-Jun/AP-1 activity may play a role in cell transformation by polyoma virus.

Documentos Relacionados

• Polyomavirus middle-sized tumor antigen modulates c-Jun phosphorylation and transcriptional activity.
• Differential subcellular localization of in vivo-phosphorylated and nonphosphorylated middle-sized tumor antigen of polyoma virus and its relationship to middle-sized tumor antigen phosphorylating activity in vitro.
• Tyrosine phosphorylation within the amino-terminal domain of pp60c-src molecules associated with polyoma virus middle-sized tumor antigen.
• Transformation by polyoma virus is drastically reduced by substitution of phenylalanine for tyrosine at residue 315 of middle-sized tumor antigen.
• c-Jun NH2-Terminal Kinase Is Essential for the Regulation of AP-1 by Tumor Necrosis Factor