Previous Article | Next Article ![]()
Journal of Virology, December 1999, p. 9917-9927, Vol. 73, No. 12
Department Biochemistry and Molecular
Biology, UMDNJ-New Jersey Medical School, Newark, New Jersey
071031; Department of Hepatitis and
Retroviruses, Pasteur Institute, Tehran, Iran2;
National Cancer Institute, National Institutes of Health,
Bethesda, Maryland 208743; and
Department of Virology, Niigata University School of
Medicine, Asahimachi-Dori, Niigata, Japan
951-85104
Received 15 June 1999/Accepted 27 August 1999
Human T-cell leukemia virus type 1 (HTLV-1) is the etiologic agent
for adult T-cell leukemia/lymphoma (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis. Tax1 is a 40-kDa
phosphoprotein, predominantly localized in the nucleus of the host
cell, which functions to transactivate both viral and cellular
promoters. It seems likely that HTLV-1, through expression of the viral
regulatory protein Tax1, provides some initial alteration
in cell metabolism predisposing the development of ATL. Here, we
demonstrate that HTLV-1 infection in T-cell lines and patient samples
causes overexpression of an early G1 cyclin, cyclin D2.
The transcriptional up-regulation of the cyclin D2 gene is
due to activation of Tax on the cyclin D2 gene. More important, we
find that overexpression of cyclin D2 is accompanied by acquisition of
new partners such as cyclin-dependent kinase 2 (cdk2), cdk4, and cdk6
in infected cells. This is in contrast to uninfected T cells, where
cyclin D2 associates only with cdk6. Functional effects of these
cyclin-cdk complexes in infected cells are shown by
hyperphosphorylation of Rb and histone H1, indicators of active
progression into S phase as well as changes in cellular chromatin and
transcription machinery. These studies link HTLV-1 infection with
changes of cellular cyclin gene expression, hence providing clues to
development of T-cell leukemia.
0022-538X/99/$04.00+0
Copyright © 1999, American Society for Microbiology. All rights reserved.
Transcriptional Up-Regulation of the Cyclin D2 Gene and
Acquisition of New Cyclin-Dependent Kinase Partners in Human T-Cell
Leukemia Virus Type 1-Infected Cells
*
Corresponding author. Mailing address: Department of
Biochemistry and Molecular Biology, UMDNJ
New Jersey Medical School, MSB E-635, Newark, NJ 07103. Phone: (973) 972-1089. Fax: (973) 972-1172. E-mail: kashanfa{at}njmsa.umdnj.edu.
This article has been cited by other articles:
| J. Bacteriol. | Mol. Cell. Biol. | Microbiol. Mol. Biol. Rev. |
|---|
| Clin. Vaccine Immunol. | ALL ASM JOURNALS |
|---|