Early Growth Response Genes Regulate B Cell Development, Proliferation, and Immune Response This information is current as Murali Gururajan, Alan Simmons, Trivikram Dasu, Brett T. of September 29, 2021. Spear, Christopher Calulot, Darrell A. Robertson, David L. Wiest, John G. Monroe and Subbarao Bondada J Immunol 2008; 181:4590-4602; ; doi: 10.4049/jimmunol.181.7.4590 http://www.jimmunol.org/content/181/7/4590 Downloaded from References This article cites 59 articles, 28 of which you can access for free at: http://www.jimmunol.org/content/181/7/4590.full#ref-list-1 http://www.jimmunol.org/ Why The JI? Submit online. • Rapid Reviews! 30 days* from submission to initial decision • No Triage! Every submission reviewed by practicing scientists • Fast Publication! 4 weeks from acceptance to publication by guest on September 29, 2021 *average Subscription Information about subscribing to The Journal of Immunology is online at: http://jimmunol.org/subscription Permissions Submit copyright permission requests at: http://www.aai.org/About/Publications/JI/copyright.html Email Alerts Receive free email-alerts when new articles cite this article. Sign up at: http://jimmunol.org/alerts The Journal of Immunology is published twice each month by The American Association of Immunologists, Inc., 1451 Rockville Pike, Suite 650, Rockville, MD 20852 Copyright © 2008 by The American Association of Immunologists All rights reserved. Print ISSN: 0022-1767 Online ISSN: 1550-6606. The Journal of Immunology Early Growth Response Genes Regulate B Cell Development, Proliferation, and Immune Response1 Murali Gururajan,2*†‡ Alan Simmons,*‡ Trivikram Dasu,3*‡ Brett T. Spear,*†§ Christopher Calulot,* Darrell A. Robertson,*‡ David L. Wiest,¶ John G. Monroe,ሻ and Subbarao Bondada4*†‡§ Egr-1 (early growth response gene-1) is an immediate early gene encoding a zinc finger motif-containing transcription factor. Upon cross-linking of BCR, mature B cells undergo proliferation with an increase in Egr-1 message. Immature B lymphoma cells that express Egr-1 message and protein constitutively are growth inhibited when Egr-1 is down-regulated by negative signals from BCR or by antisense oligonucleotides. To test the hypothesis that Egr-1 is important for B cell development, we examined B cells from primary and secondary lymphoid organs in Egr-1؊/؊ mice. Marginal zone B cell development was arrested in these mice, whereas the B cells in all other compartments were increased. To test the hypothesis that Egr-1 function may be partially compensated by other Egr family Downloaded from members, we developed transgenic mice expressing a dominant negative form of Egr-1, which lacks the trans activation domain but retains the DNA-binding domain, in a B cell-specific manner. There was a decrease in B lymphopoiesis in the bone marrow accompanied by a reduction in splenic immature and mature B cells as well as marginal zone B cells in the transgenic mice. Moreover, transgenic mice respond poorly to BCR cross-linking in vitro and T-independent and T-dependent Ags in vivo. The Journal of Immunology, 2008, 181: 4590–4602. http://www.jimmunol.org/ n response to infection, B and T cells undergo rapid prolif- lational modification (5). Acetylation of Egr-1 by CBP and p300 eration and subsequent differentiation leading to the genera- upon serum stimulation increases its stability and promotes cell I tion of effector cells that successfully combat the infection. survival, whereas phosphorylation of Egr-1 after UV radiation re- Many cell types including lymphocytes express a specific class of presses p300/CBP transcription and favors cell death (5). Egr-1 has genes called immediate early genes in response to stimulation via been shown to be important for prostate tumorigenesis, because Ag receptor, growth factor, and cytokines (1). Immediate early genes knockout mice have delayed tumorigenesis when crossed to trans- are rapidly induced (within minutes), and their induction does not genic adenocarcinoma mouse prostate model mice, which sponta- require new protein synthesis. Genes included within this category are neously develop prostate invasive neoplasia (6). c-fos and Egr-1. The Egr-1 gene-encoded protein Egr-1, a nuclear Egr-1 is expressed ubiquitously by many cell types, whereas Egr-2 by guest on September 29, 2021 zinc finger-containing transcription factor, binds to the consensus and Egr-3 are restricted in their expression (7). Even though Egr DNA motif GCGGTGGGCG and modulates the transcriptional ac- family members share redundancy in their functions as evidenced tivity of several target genes including IL-2, CD44, ICAM-1, and by 90% homology in their DNA-binding region, they do have TNF-␣ in B lymphocytes (1). Target genes for EGR-1 identified in unique functions as revealed by specific phenotypes in knockout other cell types include c-Myc, cyclin D2, p19, and cyclin G2 (2–4). mice. Egr-1Ϫ/Ϫ mice are characterized by female infertility, Egr-1 has both antiapoptotic and proapoptotic roles in different Egr2Ϫ/Ϫ mice have hindbrain abnormalities, Egr-3Ϫ/Ϫ mice have cell types depending on the nature of the stimulus. Egr-1 can up- motor neuron disorders, and Egr-4Ϫ/Ϫ mice have male infertility or down-regulate transcription of p300 and cAMP-responsive el- (8). Mice homozygous for Egr-2 deficiency die during the first 2 ement-binding protein (CBP)5 based on the nature of its posttrans- wk after birth due to brain abnormalities (9). The importance of EGR-1 in T cell biology has been studied quite extensively. Egr-1 is expressed in thymocytes and peripheral Departments of *Microbiology, Immunology, and ‡Molecular Genetics, Sanders Brown Center on Aging, †Graduate Center for Toxicology, and §Markey Cancer T cells, and its expression is rapidly induced upon TCR engage- Center, University of Kentucky, Lexington, KY 40536; ¶Basic Science Division, Fox ment in an ERK-dependent manner (10). Egr-1-deficient mice ʈ Chase Cancer Center, Philadelphia, PA 19111; and Pathology and Laboratory Med- have defects in positive selection beyond the ␤ selection check- icine, University of Pennsylvania, Philadelphia, PA 19104 point, resulting in a reduced percentage of CD4 and CD8 single- Received for publication December 4, 2007. Accepted for publication July 30, 2008. positive mature cells in the thymus (11). On TCR-transgenic back- 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 grounds, Egr-1-deficient mice express reduced numbers of naive T with 18 U.S.C. Section 1734 solely to indicate this fact. cells. Egr-1 overexpression in thymus under lck promoter allowed 1 This work was supported by National Institutes of Health Grants AI 21490, AG positive selection of thymocytes, possibly by lowering the thresh- 05731, and CA 92372 (to S.B.). old of avidity required for positive selection in the thymus (12). 2 Current address: Department of Pathology, Emory University, 1462 Clifton Road Although Egr-1-deficient animals have a low percentage of mature N.E., DSB 405, Atlanta, GA 30322. thymocytes, the absolute number of mature thymocytes is only 3 Current address: Clinical Immunology Laboratory, Rosalind Franklin University of slightly reduced due to an increase in thymus size. Recently, Medicine and Science, 3333 Green Bay Road, North Chicago, IL 60064. 4 Address correspondence and reprint requests to Dr. Subbarao Bondada, Room 303 Combs Cancer Building, Markey Cancer Research Center, University of Kentucky, lymphoid progenitors; EBF, early B cell transcription factor; DL1, delta-like 1; PFC, Lexington, KY 40536-0096. E-mail address: [email protected] plaque-forming cell. 5 Abbreviations used in this paper: CBP, cAMP-responsive element-binding protein; DN, dominant negative; MZ, marginal zone; TNP, trinitrophenyl; CLP, common Copyright © 2008 by The American Association of Immunologists, Inc. 0022-1767/08/$2.00 www.jimmunol.org The Journal of Immunology 4591 Downloaded from http://www.jimmunol.org/ by guest on September 29, 2021 FIGURE 1. Altered B cell subsets in the bone marrow and spleen of Egr-1Ϫ/Ϫ mice. Flow cytometric analysis of bone marrow cells obtained from Egr-1Ϫ/Ϫ and littermate controls stained with CyChrome anti-B220 and PE anti-IgM. B220ϩIgMϪ cells represent pre-pro B, pro-B, and pre-B cells. B220ϩIgMϩ cells represent immature B, transitional, and recirculating mature B cells (A). Bone marrow cells were stained with PE-Cy anti-B220, 4592 B CELL INTRINSIC ROLE FOR Egr Schnell et al demonstrated that Egr-1 is required for survival of marrow of Cre-LoxP conditional transgenic mice in which Cre mature thymocytes and newly emigrated thymocytes (13). All four activation leads to H chain deletion (29). These data show that family members are induced upon TCR ligation. Overexpression Egr-1 is important for B cell survival and that Egr-1 induction of Egr-2 and Egr-3 is associated with an increase in the E3 ubiq- downstream of BCR might be important for B cell development. uitin ligase Cbl-b and inhibition of T cell activation. Also, T cells Despite these studies, the in vivo role of Egr-1 during B cell de- from Egr-3Ϫ/Ϫ mice display lower Cbl-b and are resistant to in velopment and functional responses remains to be elucidated. vivo peptide-induced tolerance (14). These data support the idea Although Egr-1Ϫ/Ϫ mice have been generated, no significant that Egr-2 and Egr-3 are involved in promoting TCR-induced neg- effect of Egr-1 deficiency on B cell development has been reported ative signaling. The role of Egr-1 in macrophage differentiation (30). This could be due to the redundancy of Egr-1 function given has also been studied in detail. Using a variety of differentiation- that this family has three other members with similar transcrip- inducible myeloid cell lines, Krishnaraju et al.