Recruitment of the de novo DNA methyltransferase Dnmt3a by Kaposi's sarcoma-associated herpesvirus LANA
- Viral Oncology Program, Sidney Kimmel Cancer Center, Johns Hopkins School of Medicine, Baltimore, MD 21231
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Edited by George Klein, Karolinska Institutet, Stockholm, Sweden, and approved August 7, 2006 (received for review May 31, 2006)
Abstract
The Kaposi's sarcoma-associated herpesvirus LANA protein is expressed in all Kaposi's sarcoma-associated herpesvirus-infected cells, including the tumor cells of endemic and AIDS-associated Kaposi sarcoma, primary effusion lymphoma, and Castleman disease. LANA modulates cell gene expression, but the mechanisms of LANA-mediated transcriptional reprogramming are poorly understood. LANA-repressed cell genes were identified by using retroviral-transduced telomerase-immortalized microvascular endothelial cells. Transciptional repression of targeted genes was relieved by treatment with the methyltransferase inhibitor 5-aza-2′-deoxycytidine, suggesting a role for DNA methylation in repression. We found that LANA coprecipitated with DNA methyltransferases (Dnmts) and recruited endogenous DNA methyltransferase activity from the cell extract. LANA preferentially relocalized Dnmt3a from the nuclear matrix into the chromatin fraction. Further, LANA associated with repressed cellular promoters, recruited Dnmt3a to DNA, and facilitated de novo promoter methylation of a down-regulated gene, cadherin 13 (H-cadherin). The data provide an example of promoter-specific epigenetic DNA modification through viral protein recruitment of de novo Dnmt activity.
Footnotes
- *To whom correspondence should be addressed. E-mail: dhayward{at}jhmi.edu
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Author contributions: M.S. and S.D.H. designed research; M.S., A.K., and J.Z. performed research; A.K. contributed new reagents/analytic tools; M.S. analyzed data; and S.D.H. wrote the paper.
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Conflict of interest statement: No conflicts declared.
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This paper was submitted directly (Track II) to the PNAS office.
- Abbreviations:
- AZA,
- 5-aza-2′-deoxycytidine;
- KSHV,
- Kaposi's sarcoma-associated herpesvirus;
- TIME-LANA,
- LANA-converted, telomerase-immortalized, microvascular endothelial;
- TSA,
- trichostatin A.
- © 2006 by The National Academy of Sciences of the USA
