Pim-1 kinase inhibits the activation of reporter gene expression in Elk-1 and c-Fos reporting systems but not the endogenous gene expression: an artifact of the reporter gene assay by transient co-transfection
AUTOR(ES)
Yan, B., Wang, H., Kon, T., Li, C.-Y.
FONTE
Brazilian Journal of Medical and Biological Research
DATA DE PUBLICAÇÃO
2006-02
RESUMO
We have studied the molecular mechanism and signal transduction of pim-1, an oncogene encoding a serine-threonine kinase. This is a true oncogene which prolongs survival and inhibits apoptosis of hematopoietic cells. In order to determine whether the effects of Pim-1 occur by regulation of the mitogen-activated protein kinase pathway, we used a transcriptional reporter assay by transient co-transfection as a screening method. In this study, we found that Pim-1 inhibited the Elk-1 and NFkappaB transcriptional activities induced by activation of the mitogen-activated protein kinase cascade in reporter gene assays. However, Western blots showed that the induction of Elk-1-regulated expression of endogenous c-Fos was not affected by Pim-1. The phosphorylation and activation of neither Erk1/2 nor Elk-1 was influenced by Pim-1. Also, in the gel shift assay, the pattern of endogenous NFkappaB binding to its probe was not changed in any manner by Pim-1. These data indicate that Pim-1 does not regulate the activation of Erk1/2, Elk-1 or NFkappaB. These contrasting results suggest a pitfall of the transient co-transfection reporter assay in analyzing the regulation of transcription factors outside of the chromosome context. It ensures that results from reporter gene expression assay should be verified by study of endogenous gene expression.
Documentos Relacionados
- C/EBPBeta and Elk-1 synergistically transactivate the c-fos serum response element
- Induction of c-fos expression through JNK-mediated TCF/Elk-1 phosphorylation.
- Glutamate Induces Phosphorylation of Elk-1 and CREB, Along with c-fos Activation, via an Extracellular Signal-Regulated Kinase-Dependent Pathway in Brain Slices
- Cationic lipid-mediated co-transfection of insect cells.
- A burst of c-fos gene expression in the mouse occurs at birth.
