Abstract |
Polyomavirus JC (JCV) causes the human demyelinating disease, progressive multifocal leukoencephalopathy (PML). The recent demonstration of cases of PML in association with human T-lymphotropic virus type I ( HTLV-I) infection prompted us to examine whether the HTLV-I-encoded regulatory protein Tax activates JCV transcription. By employing a dual luciferase assay, we initially found that the expression of Tax activated the transcriptional potential of both early and late promoters of JCV in human neuronal but not in non-neuronal cells. We subsequently analyzed the mechanism of Tax-induced activation of the JCV promoter in neuronal cells with the following results: 1) the JCV promoter that lacks the NF-kappaB-binding motif could not be activated by Tax; 2) the overexpression of IkappaBalpha abolished Tax-induced transcriptional activation of the JCV promoter; 3) a Tax mutant (M22) lacking the potential for activation via the NF-kappaB pathway did not activate the JCV promoter. Furthermore, Tax enhances the gene expression of JCV T antigen and VP1. We examined mechanisms of the cell-specific activation of the JCV promoter by Tax. Electrophoretic mobility shift assay demonstrated the presence of Tax-bound protein(s) that were specifically present in non-neuronal cells. This study is the first demonstration of the activation of JCV promoter by HTLV-I Tax in an NF-kappaB-dependent manner.
|
Authors | Y Okada, H Sawa, S Tanaka, A Takada, S Suzuki, H Hasegawa, T Umemura, J Fujisawa, Y Tanaka, W W Hall, K Nagashima |
Journal | The Journal of biological chemistry
(J Biol Chem)
Vol. 275
Issue 22
Pg. 17016-23
(Jun 02 2000)
ISSN: 0021-9258 [Print] United States |
PMID | 10828075
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
|
Chemical References |
- DNA Primers
- DNA, Viral
- Gene Products, tax
|
Topics |
- Base Sequence
- DNA Primers
- DNA, Viral
(genetics)
- Gene Products, tax
(metabolism)
- Humans
- JC Virus
(genetics)
- Neurons
(metabolism)
- Promoter Regions, Genetic
- Sequence Deletion
- Transcriptional Activation
- Tumor Cells, Cultured
|