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Blood, 15 September 2007, Vol. 110, No. 6, pp. 2110-2120.
Prepublished online as a Blood First Edition Paper on May 31, 2007; DOI 10.1182/blood-2006-11-058388.
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Submitted November 28, 2006
Accepted May 17, 2007
Negative regulation of the SH2-homology-containing protein-tyrosine phosphatase-1 (SHP-1) P2 promoter by the HTLV-1 tax oncoprotein
Jihua Cheng, Andre R. Kydd, Koichi Nakase, Kristin M. Noonan, Akikazu Murakami, Hong Tao, Markryan Dwyer, Chen Xu, Quan Zhu, and Wayne A. Marasco*
Department of Cancer Immunology & AIDS, Dana-Farber Cancer Institute, Boston, MA, United States
Department of Medicine, Harvard Medical School, Boston, MA, United States
* Corresponding author; email: wayne_marasco{at}dfci.harvard.edu.
Expression of SH2-Homology-Containing Protein-Tyrosine Phosphatase-1 (SHP-1), a candidate tumor suppressor, is repressed in HTLV-1 transformed lymphocyte cell lines, Adult T-cell Leukemia (ATL) cells and in other hematological malignancies. However, the mechanisms underlying regulation and repression of SHP-1 remain unclear. Herein, we cloned the putative full-length, hematopoietic cell specific SHP-1 P2 promoter and identified the "core" promoter regions. HTLV-1 Tax profoundly represses P2 promoter activity and histone deacetylase-1 (HDAC1) potentiates such inhibition. NF- B was implicated as both a rate-limiting factor for basal P2 promoter activity and important for Tax-induced Promoter Silencing (TIPS). Chromatin Immunoprecipitation studies demonstrated that NF- B dissociates from the SHP-1 P2 promoter following the binding of Tax and HDAC1. This is in agreement with co-immunoprecipitation study where NF- B competed with HDAC1 for association with Tax protein. We propose that in TIPS, Tax recruits HDAC1 to the SHP-1 P2 promoter and forms an inhibitory complex that results in deacetylation and dissociation of NF- B from the promoter and attenuation of SHP-1 expression. TIPS provides a possible first step toward HTLV-1 leukemogenesis through its down modulation of this key immediate early negative regulator of IL-2 signaling.

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K. Nakase, J. Cheng, Q. Zhu, and W. A. Marasco
Mechanisms of SHP-1 P2 promoter regulation in hematopoietic cells and its silencing in HTLV-1-transformed T cells
J. Leukoc. Biol.,
January 1, 2009;
85(1):
165 - 174.
[Abstract]
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