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J. Biol. Chem., Vol. 283, Issue 2, 951-962, January 11, 2008

This Article Full Text Full Text (PDF) Supplemental Data All Versions of this Article: 283/2/951    most recent M705262200v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by John, S. A. Articles by Garrett-Sinha, L. A. PubMed PubMed Citation Articles by John, S. A. Articles by Garrett-Sinha, L. A. Social Bookmarking                      What's this?

Ets-1 Regulates Plasma Cell Differentiation by Interfering with the Activity of the Transcription Factor Blimp-1^*

Shinu A. John, James L. Clements, Lisa M. Russell, and Lee Ann Garrett-Sinha¹

From the Department of Biochemistry, State University of New York, Buffalo, New York 14214 and Department of Immunology, Roswell Park Cancer Institute, Buffalo, New York 14263

Development of immunoglobulin-secreting plasma cells from B cells is a tightly regulated process controlled by the action of a number of transcription factors. In particular, the transcription factor Blimp-1 is a key positive regulator of plasmacytic differentiation via its ability to suppress expression of genes involved in the mature B cell program. The transcription factor Ets-1 is a negative regulator of plasmacytic differentiation, as indicated by the development of increased numbers of IgM-secreting plasma cells in Ets-1 knock-out mice. We have previously shown that Ets-1-deficient B cells undergo enhanced differentiation into IgM-secreting plasma cells in response to Toll-like receptor 9 (TLR9) signaling. We now explore the mechanism by which Ets-1 limits differentiation downstream of TLR9. Our results indicate that Ets-1 physically interacts with Blimp-1, which leads to a block in Blimp-1 DNA binding activity and a reduction in the ability of Blimp-1 to repress target genes without interfering with Blimp-1 protein levels. In addition, we show that Ets-1 induces the expression of several target genes that are repressed by Blimp-1, including Pax-5. These results reveal a previously unknown mechanism for the control of Blimp-1 activity by Ets-1 and suggest that expression of Ets-1 must be down-regulated before plasmacytic differentiation can occur.

Received for publication, June 27, 2007 , and in revised form, October 9, 2007.

^* This work was supported by a Lupus Research Institute grant. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement"in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

The on-line version of this article (available at http://www.jbc.org) contains supplemental Figs. S1-S3.

¹ To whom correspondence should be addressed: 140 Farber Hall, 3435 Main St., Buffalo, NY 14214. Fax: 716-829-2725; E-mail: leesinha{at}buffalo.edu.

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