Involvement of Two NF-κB Binding Elements in Tumor Necrosis Factor α-, CD40-, and Epstein-Barr Virus Latent Membrane Protein 1-mediated Induction of the Cellular Inhibitor of Apoptosis Protein 2 Gene

Abstract

The antiapoptotic function of NF-κB is believed to be mediated through the induction of antiapoptotic genes. Among the antiapoptotic genes, cellular inhibitor of apoptosis protein 2 (c-IAP2/HIAP-1/MIHC) is originally identified as a molecule recruited to the tumor necrosis factor (TNF) receptor complex, and its expression is preferentially up-regulated by TNF and other stimuli activating NF-κB. However, direct evidence of transcriptional regulation of NF-κB on the c-IAP2 gene is still missing. Here, we have cloned and characterized the promoter region required for NF-κB-dependent transcription of the c-IAP2gene. Sequencing of a 3.5-kilobase fragment of the 5′-flanking region of the c-IAP2 gene has identified a TATA-like sequence and potential binding sites for nuclear factor of activated T cells, interferon regulatory factor 1, activator protein 1, glucocorticoid response element, and three putative NF-κB binding elements. Deletion and mutational analysis of the 5′-flanking region linked to the luciferase gene revealed that transcriptional activation by TNF or interleukin 1 is mediated cooperatively by two NF-κB binding sites. Electrophoretic mobility shift assays characterized that the two NF-κB sites can be recognized and bound by the NF-κB p50/p65 heterodimer. In addition, the transcription of c-IAP2 promoter was strongly up-regulated when CD40 or Epstein-Barr virus latent membrane protein 1 was overexpressed. The antiapoptotic function of NF-κB is believed to be mediated through the induction of antiapoptotic genes. Among the antiapoptotic genes, cellular inhibitor of apoptosis protein 2 (c-IAP2/HIAP-1/MIHC) is originally identified as a molecule recruited to the tumor necrosis factor (TNF) receptor complex, and its expression is preferentially up-regulated by TNF and other stimuli activating NF-κB. However, direct evidence of transcriptional regulation of NF-κB on the c-IAP2 gene is still missing. Here, we have cloned and characterized the promoter region required for NF-κB-dependent transcription of the c-IAP2gene. Sequencing of a 3.5-kilobase fragment of the 5′-flanking region of the c-IAP2 gene has identified a TATA-like sequence and potential binding sites for nuclear factor of activated T cells, interferon regulatory factor 1, activator protein 1, glucocorticoid response element, and three putative NF-κB binding elements. Deletion and mutational analysis of the 5′-flanking region linked to the luciferase gene revealed that transcriptional activation by TNF or interleukin 1 is mediated cooperatively by two NF-κB binding sites. Electrophoretic mobility shift assays characterized that the two NF-κB sites can be recognized and bound by the NF-κB p50/p65 heterodimer. In addition, the transcription of c-IAP2 promoter was strongly up-regulated when CD40 or Epstein-Barr virus latent membrane protein 1 was overexpressed. tumor necrosis factor α cellular inhibitor of apoptosis protein TNF receptor-associated factor interleukin 1 electrophoretic mobility shift assay Epstein-Barr virus latent membrane protein 1 activator protein 1 nuclear factor of activated T cell luciferase p55 TNF receptor NF-κB-inducing kinase N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonic acid T cell receptor Stimulation of cells with tumor necrosis factor α (TNF)1 generates two seemingly conflicting signals; one that triggers apoptotic cell death and the other that antagonizes the apoptotic signal by activating transcription factor NF-κB (1.Ashkenazi A. Dixit V.M. Science. 1998; 281: 1305-1308Crossref PubMed Scopus (5168) Google Scholar). The overall outcome in a specific cell type is dependent on the balance of these two signals. In cells resistant to TNF-induced apoptosis, inhibition of NF-κB activation attenuates apoptosis resistance (2.Jeremias I. Kupatt C. Baumann B. Herr I. Wirth T. Debatin K.M. Blood. 1998; 91: 4624-4631Crossref PubMed Google Scholar). Furthermore, NF-κB subunit p65-disrupted cells are more sensitive to TNF-induced apoptosis (3.Beg A.A. Baltimore D. Science. 1996; 274: 782-784Crossref PubMed Scopus (2940) Google Scholar). The protective role of NF-κB against apoptosis is believed to be mediated by the induction of various antiapoptotic genes, includingIEX-1L (4.Wu M.X. Ao Z. Prasad K.V. Wu R. Schlossman S.F. Science. 1998; 281: 998-1001Crossref PubMed Google Scholar), Bcl-2 and Bcl-x (5.Tamatani M. Che Y.H. Matsuzaki H. Ogawa S. Okado H. Miyake S. Mizuno T. Tohyama M. J. Biol. Chem. 1999; 274: 8531-8538Abstract Full Text Full Text PDF PubMed Scopus (533) Google Scholar),A20 (6.Krikos A. Laherty C.D. Dixit V.M. J. Biol. Chem. 1992; 267: 17971-17976Abstract Full Text PDF PubMed Google Scholar), and some members of the inhibitor of apoptosis (IAP) family such as XIAP (7.Stehlik C. de Martin R. Kumabashiri I. Schmid J.A. Binder B.R. Lipp J. J. Exp. Med. 1998; 188: 211-216Crossref PubMed Scopus (593) Google Scholar), c-IAP-1, andc-IAP2 (8.Shu H.B. Takeuchi M. Goeddel D.V. Proc. Natl. Acad. Sci. U. S. A. 1996; 93: 13973-13978Crossref PubMed Scopus (367) Google Scholar, 9.Erl W. Hansson G.K. de Martin R. Draude G. Weber K.S. Weber C. Circ. Res. 1999; 84: 668-677Crossref PubMed Scopus (146) Google Scholar, 10.Chu Z.L. McKinsey T.A. Liu L. Gentry J.J. Malim M.H. Ballard D.W. Proc. Natl. Acad. Sci. U. S. A. 1997; 94: 10057-10062Crossref PubMed Scopus (826) Google Scholar). Among these, c-IAP2 (cellular inhibitor of apoptosis protein 2), also known as HIAP-1 (11.Liston P. Roy N. Tamai K. Lefebvre C. Baird S. Cherton-Horvat G. Farahani R. McLean M. Ikeda J.E. MacKenzie A. Korneluk R.G. Nature. 1996; 379: 349-353Crossref PubMed Scopus (872) Google Scholar) and MIHC (12.Uren A.G. Pakusch M. Hawkins C.J. Puls K.L. Vaux D.L. Proc. Natl. Acad. Sci. U. S. A. 1996; 93: 4974-4978Crossref PubMed Scopus (447) Google Scholar), was initially identified as a molecule that is recruited to the TNF receptor via its association with the TNF receptor-associated factors, TRAF1 and TRAF2 (13.Rothe M. Pan M.G. Henzel W.J. Ayres T.M. Goeddel D.V. Cell. 1995; 83: 1243-1252Abstract Full Text PDF PubMed Scopus (1057) Google Scholar). TRAF molecules are proposed to function as adapter proteins conveying the TNF receptor-mediated signals (14.Rothe M. Sarma V. Dixit V.M. Goeddel D.V. Science. 1995; 269: 1424-1471Crossref PubMed Scopus (980) Google Scholar). It has been suggested that c-IAP2 can inhibit apoptosis by modulating the TNF-induced NF-κB activity (10.Chu Z.L. McKinsey T.A. Liu L. Gentry J.J. Malim M.H. Ballard D.W. Proc. Natl. Acad. Sci. U. S. A. 1997; 94: 10057-10062Crossref PubMed Scopus (826) Google Scholar). It was observed that, in Jurkat T cells, TNF treatment led to NF-κB-dependent induction ofc-IAP2 gene, and conversely, c-IAP2 was able to activate NF-κB via an IκBα-targeting mechanism; this consequently suppressed TNF-induced apoptosis. Later studies showed that c-IAP2 exhibits its antiapoptotic function by directly binding and inhibiting downstream cell death protease caspases-3, -7, and -9, but not upstream protease caspase-8, which is implicated in TNF-induced cell death signaling (15.Roy N. Deveraux Q.L. Takahashi R. Salvesen G.S. Reed J.C. EMBO J. 1997; 16: 6914-6925Crossref PubMed Scopus (1140) Google Scholar, 16.Deveraux Q.L. Roy N. Stennicke H.R. Van Arsdale T. Zhou Q. Srinivasula S.M. Alnemri E.S. Salvesen G.S. Reed J.C. EMBO J. 1998; 17: 2215-2223Crossref PubMed Scopus (1246) Google Scholar). However, a recent study suggests that c-IAP2 requires TRAF1, TRAF2, and c-IAP1 activities for the full suppression of TNF-induced cell death at the level of caspase-8, all of which are transcriptionally activated by NF-κB (17.Wang C.Y. Mayo M.W. Korneluk R.G. Goeddel D.V. Baldwin Jr., A.S. Science. 1998; 281: 1680-1683Crossref PubMed Scopus (2584) Google Scholar). In cells in which NF-κB activation was prevented with dominant negative IκBα, ectopic expression of c-IAP-1, c-IAP2, TRAF1 and TRAF2 together fully suppressed TNF-induced apoptosis and caspase-8 activation, substituting for the antiapoptotic effect of NF-κB. In the same cells, however, either c-IAP1 or c-IAP2 alone was sufficient to suppress etoposide-induced cell death by direct inhibition of caspase-3 (17.Wang C.Y. Mayo M.W. Korneluk R.G. Goeddel D.V. Baldwin Jr., A.S. Science. 1998; 281: 1680-1683Crossref PubMed Scopus (2584) Google Scholar). These results support the hypothesis that NF-κB activates a group of gene products that function cooperatively to suppress TNF-induced apoptosis by inhibiting the activation of upstream death protease caspase-8. In contrast to the mode of action of c-IAP2, little is known about how c-IAP2 is regulated, except that it is under the control of NF-κB. Transcription of c-IAP2 gene was found to be also up-regulated by treating endothelial cells with interleukin 1 (IL-1) or lipopolysaccharide (18.Stehlik C. de Martin R. Kumabashiri I. Schmid J.A. Binder B.R. Lipp J. J. Exp. Med. 1998; 188: 211-216Crossref PubMed Scopus (572) Google Scholar) and by CD40 stimulation on B lymphocytes (19.Craxton A. Shu G. Graves J.D. Saklatvala J. Krebs E.G. Clark E.A. J. Immunol. 1998; 161: 3225-3236PubMed Google Scholar), which are stimuli that lead to NF-κB activation. It has been demonstrated that the transcriptional activation of other antiapoptotic genes such as A20, Bcl-X, and Bfl/A1 by NF-κB is through one or two NF-κB binding sites resided in their promoter regions (5.Tamatani M. Che Y.H. Matsuzaki H. Ogawa S. Okado H. Miyake S. Mizuno T. Tohyama M. J. Biol. Chem. 1999; 274: 8531-8538Abstract Full Text Full Text PDF PubMed Scopus (533) Google Scholar, 20.Chen F. Demers L.M. Vallyathan V. Lu Y. Castranova V. Shi X. J. Biol. Chem. 1999; 274: 35591-35595Abstract Full Text Full Text PDF PubMed Scopus (51) Google Scholar, 21.Lee H.H. Dadgostar H. Cheng Q. Shu J. Cheng G. Proc. Natl. Acad. Sci. U. S. A. 1999; 96: 9136-9141Crossref PubMed Scopus (485) Google Scholar). It remains to be elucidated, however, whether a similar transcription-regulating mechanism is involved inc-IAP2 gene expression. Although the partial 5′-flanking region surrounding the putative transcription start site ofc-IAP2 was reported (22.Young S.S. Liston P. Xuan J.Y. McRoberts C. Lefebvre C.A. Korneluk R.G. Mamm. Genome. 1999; 10: 44-48Crossref PubMed Scopus (34) Google Scholar), the sequence information was not enough to gain an understanding of the regulation of c-IAP2gene expression. In the present study, we sequenced the 5′-flanking region (3.5 kilobases (kb)) of the c-IAP2 gene. Deletion analysis revealed that the region conferring inducibility by TNF or IL-1 is localized downstream the proposed transcription start site and three putative NF-κB binding sites and other potential transcription factor binding elements. Electrophoretic mobility shift assays and analysis of the NF-κB binding sites demonstrated that two NF-κB are required for promoter activity and that function cooperatively in TNF-induced activation. we showed that the activity is strongly in cells with expression for CD40 and Epstein-Barr virus latent membrane protein 1 cells and cells in with and TNF was by H. H. of was was other not for was W. G. cells was with the full c-IAP2 of and and characterized by and The fragment was and cloned as a potential fragment promoter region the region of the c-IAP2gene. analysis revealed that a site the fragment the site to the of the sequence The fragment upstream of the was with the and cloned to the sites of in of the on by the of of various of the 5′-flanking region of c-IAP2 promoter by the luciferase The fragment was cloned the and sites of The and the in and a the with various and a to the promoter sequence that is downstream of the sites of are the a site at their to to to to to and to and and and the sites of was by the acid as 2 of luciferase was with of Y.H. K. Y. J. 1995; Google Scholar) when the cells TNF or IL-1 was for as in of and at for to cell The for luciferase and and the of the luciferase assay with to the of the assay for of and cells with TNF at the as by J.D. R.G. Res. PubMed Scopus Google Scholar), by the assay and at The for to the three potential NF-κB binding sites in the c-IAP2 promoter site and NF-κB site and NF-κB site and to other to a was by treatment of kinase in the of 1 of the was with of nuclear protein in a of of the binding 1 2 of for the was on a with 1 The was and to a of was to the of the as of was to the the of the in these of the 5′-flanking region of the c-IAP2 gene, a cell was with a against the full c-IAP2 and analysis of strongly led to the of one which the 5′-flanking region of with various of the cloned and their partial 1 the of to the reported by (22.Young S.S. Liston P. Xuan J.Y. McRoberts C. Lefebvre C.A. Korneluk R.G. Mamm. Genome. 1999; 10: 44-48Crossref PubMed Scopus (34) Google Scholar). it has been reported gene is by TNF (10.Chu Z.L. McKinsey T.A. Liu L. Gentry J.J. Malim M.H. Ballard D.W. Proc. Natl. Acad. Sci. U. S. A. 1997; 94: 10057-10062Crossref PubMed Scopus (826) Google Scholar, C.Y. Mayo M.W. Korneluk R.G. Goeddel D.V. Baldwin Jr., A.S. Science. 1998; 281: 1680-1683Crossref PubMed Scopus (2584) Google Scholar), we initially to whether the region upstream the of the the promoter activity conferring TNF inducibility by gene The fragment and its or linked to gene in the and the cell cells with TNF for and for TNF-induced luciferase expression. in 1 the fragment showed a promoter the luciferase activity by TNF The promoter activity TNF inducibility not with the of the the in which the region was the of a However, the upstream of the putative transcription start the of (22.Young S.S. Liston P. Xuan J.Y. McRoberts C. Lefebvre C.A. Korneluk R.G. Mamm. Genome. 1999; 10: 44-48Crossref PubMed Scopus (34) Google Scholar), revealed promoter the of the promoter region we the with either NF-κB-inducing kinase or NF-κB subunit and the cells for luciferase in 1 and able to activate luciferase expression in cells with but not in cells with the that the promoter region conferring NF-κB-dependent transcriptional activation ofc-IAP2 gene downstream of the proposed transcription start The of the 5′-flanking region of the c-IAP2 gene was The sequence a of of and their regulatory regions but to the transcription start site by analysis to the of the of the region of c-IAP2 is to be however, we the sequence for the that was as a of the on this a TATA-like was identified at potential regulatory found by the interferon regulatory at and potential binding sites for activator and and nuclear factor of activated T cells binding sites and as as a glucocorticoid three putative NF-κB binding sites identified at and regulatory regions the 5′-flanking sequence of c-IAP2, which TNF or IL-1 or cells with of of the c-IAP2 promoter linked to gene. The of the 5′-flanking region the to of the cells with the three that with or with luciferase activity by TNF or IL-1 was with the B and However, which in to the also the interferon regulatory factor site and NF-κB site mediated TNF and promoter activity as by a to in luciferase activity the of the an NF-κB site in a similar induction with the the all the potential NF-κB sites 1, and a in luciferase activity observed with the and TNF or IL-1 treatment to induction in and cells by induction in cells by with the the level of luciferase activity not that the transcriptional activation of the c-IAP2gene by TNF and IL-1 are and in which more one NF-κB binding sites are The results in the stimulation of the luciferase activity in cells by TNF the control the of to the of in the the stimulation by TNF to that or transcriptional activation ofc-IAP2 gene expression be by NF-κB binding resided in the 5′-flanking region and we which of the potential NF-κB sites the the to the of which one or two NF-κB The NF-κB at site 2 the full TNF or IL-1 inducibility as or that with the type the at sites 1 and that the NF-κB site 2 is not of the NF-κB at sites 1 and in of promoter activity by and inducibility by TNF was still These results that sites are for activity by TNF and that cooperatively gene expression. whether nuclear proteins to the NF-κB binding in was with nuclear of or cells specific the NF-κB at sites 1, and that with TNF for in the induction of nuclear protein that bound to NF-κB sites 1 and but not to the site assays type of sites 1 and in of the the not have the binding of nuclear proteins to the NF-κB sites 1 and These results are with the mutational analysis of the NF-κB sites in which the NF-κB at site 1 and site in the transcriptional activation TNF the nuclear protein bound to the NF-κB sites 1 and assay was against NF-κB proteins and and an B that with the or the level of of NF-κB sites 1 and Furthermore, when with the However, of NF-κB and the not of proteins with NF-κB sites 1 or similar results in cell nuclear results that the NF-κB sites 1 and be bound by the NF-κB p50/p65 in cell that c-IAP2 is up-regulated by CD40 stimulation in B lymphocytes (19.Craxton A. Shu G. Graves J.D. Saklatvala J. Krebs E.G. Clark E.A. J. Immunol. 1998; 161: 3225-3236PubMed Google Scholar), we whether of CD40 is of promoter also whether Epstein-Barr virus can the c-IAP2 promoter is known to be involved in B cell K. K.M. Proc. Natl. Acad. U. S. A. PubMed Scopus Google Scholar) and the antiapoptotic genes and NF-κB activation C.D. F. Dixit V.M. J. Biol. Chem. 1992; 267: Full Text PDF PubMed Google Scholar, S. M. C. D. F. R. A. Cell. Full Text PDF PubMed Scopus Google Scholar). cells with the CD40 or with either the or its is the expression expression NF-κB activation and apoptotic signaling in the cells Y.H. K. Y. J. 1995; Google Scholar, I. Y. D. J. Biol. Chem. 1995; Full Text Full Text PDF PubMed Scopus Google Scholar). that of or in cells in a luciferase gene expression by the but not by its promoter in which two NF-κB sites a NF-κB-dependent c-IAP2 promoter activation by CD40 and It is that NF-κB to its antiapoptotic function through the induction of antiapoptotic genes, which c-IAP2, and (4.Wu M.X. Ao Z. Prasad K.V. Wu R. Schlossman S.F. Science. 1998; 281: 998-1001Crossref PubMed Google Scholar, M. Che Y.H. Matsuzaki H. Ogawa S. Okado H. Miyake S. Mizuno T. Tohyama M. J. Biol. Chem. 1999; 274: 8531-8538Abstract Full Text Full Text PDF PubMed Scopus (533) Google Scholar, A. Laherty C.D. Dixit V.M. J. Biol. Chem. 1992; 267: 17971-17976Abstract Full Text PDF PubMed Google Scholar, C. de Martin R. Kumabashiri I. Schmid J.A. Binder B.R. Lipp J. J. Exp. Med. 1998; 188: 211-216Crossref PubMed Scopus (593) Google Scholar, H.B. Takeuchi M. Goeddel D.V. Proc. Natl. Acad. Sci. U. S. A. 1996; 93: 13973-13978Crossref PubMed Scopus (367) Google Scholar, 9.Erl W. Hansson G.K. de Martin R. Draude G. Weber K.S. Weber C. Circ. Res. 1999; 84: 668-677Crossref PubMed Scopus (146) Google Scholar, 10.Chu Z.L. McKinsey T.A. Liu L. Gentry J.J. Malim M.H. Ballard D.W. Proc. Natl. Acad. Sci. U. S. A. 1997; 94: 10057-10062Crossref PubMed Scopus (826) Google Scholar). Among members of the c-IAP2 is in the that, not is its expression under the control of NF-κB but also c-IAP2 can activate NF-κB (10.Chu Z.L. McKinsey T.A. Liu L. Gentry J.J. Malim M.H. Ballard D.W. Proc. Natl. Acad. Sci. U. S. A. 1997; 94: 10057-10062Crossref PubMed Scopus (826) Google Scholar). to the c-IAP2 is by a of NF-κB-inducing and in cell induction of c-IAP1 and XIAP to be and (8.Shu H.B. Takeuchi M. Goeddel D.V. Proc. Natl. Acad. Sci. U. S. A. 1996; 93: 13973-13978Crossref PubMed Scopus (367) Google Scholar, 9.Erl W. Hansson G.K. de Martin R. Draude G. Weber K.S. Weber C. Circ. Res. 1999; 84: 668-677Crossref PubMed Scopus (146) Google Scholar, 10.Chu Z.L. McKinsey T.A. Liu L. Gentry J.J. Malim M.H. Ballard D.W. Proc. Natl. Acad. Sci. U. S. A. 1997; 94: 10057-10062Crossref PubMed Scopus (826) Google Scholar, C. de Martin R. Kumabashiri I. Schmid J.A. Binder B.R. Lipp J. J. Exp. Med. 1998; 188: 211-216Crossref PubMed Scopus (572) Google Scholar, A. Shu G. Graves J.D. Saklatvala J. Krebs E.G. Clark E.A. J. Immunol. 1998; 161: 3225-3236PubMed Google Scholar, Baird S. Korneluk R.G. MacKenzie 1998; 17: PubMed Scopus Google Scholar, Q.L. Reed J.C. 1999; PubMed Scopus Google Scholar). such that c-IAP2 gene is preferentially up-regulated by NF-κB the direct evidence of transcriptional regulation of NF-κB on c-IAP2 is still missing. The of this study was to and the 5′-flanking region of the c-IAP2 gene and to the for transcriptional activation of gene. the of c-IAP2 gene was reported by (22.Young S.S. Liston P. Xuan J.Y. McRoberts C. Lefebvre C.A. Korneluk R.G. Mamm. Genome. 1999; 10: 44-48Crossref PubMed Scopus (34) Google Scholar). the putative transcription start site by of and the partial sequence information upstream of their proposed start In however, the upstream of the proposed transcription start site not promoter activity as as NF-κB-dependent gene activation, the downstream the proposed transcription start site direct the transcriptional activation of the c-IAP2gene stimulation of cells with TNF or of or In addition, the downstream region the proposed start site a of to the promoter a TATA-like found in for L. J. J. Biol. Chem. Full Text PDF PubMed Google Scholar), kinase Cell. Biol. 10: PubMed Scopus Google Scholar), and genes J. Biol. Chem. 1996; Full Text Full Text PDF PubMed Scopus Google Scholar). results strongly that the promoter region of the c-IAP2 gene, which NF-κB-dependent is downstream of the proposed transcription start It is that the regulatory for this expression downstream of the transcription start site or the of the c-IAP2 gene. However, this can be by transcription sites by more such as in have of its to c-IAP2 which has a region to be potential have been identified in the sequence of the 5′-flanking region of the c-IAP2 gene. The of the promoter linked to the luciferase gene revealed that the region conferring or promoter activation and of the c-IAP2 mutational analysis and of the putative NF-κB binding sites the region of the promoter identified that two NF-κB binding at and are required for promoter activity and that function cooperatively in transcriptional activation of the c-IAP2 gene. In addition, with against NF-κB characterized that the two NF-κB binding sites be recognized and bound by the NF-κB p50/p65 results direct evidence of transcriptional regulation of NF-κB on c-IAP2 gene and a of the that NF-κB as a factor in the regulation of genes involved in cell or in response to apoptotic the role of NF-κB in c-IAP2 gene expression as characterized by the present study, a recent suggests that induction of c-IAP2 gene is not dependent on NF-κB activation K. J.A. J. 1997; Google Scholar). c-IAP2 can be by to a by treatment of in a cell in the that the cells apoptosis by and K. J.A. J. 1997; Google Scholar). These results that and in to In this it is of that a glucocorticoid response at as as interferon regulatory binding sites at and identified by in the 5′-flanking promoter region of gene. can function as specific binding sites in the of the c-IAP2 5′-flanking remains to be In addition, to a recent R. K. S. G. N. P. Schmid H. J. Biol. Chem. 1999; 274: Full Text Full Text PDF PubMed Scopus Google Scholar), stimulation of T cell receptor can also c-IAP2 in the T cell It showed that the induction ofc-IAP2 gene was but that mediated by In their study, TNF and α in the not to be involved in the c-IAP2 the not the level of c-IAP2 It is that transcriptional regulation that gene expression requires signaling which activate transcription activation of and NF-κB all to gene transcription D. Immunol. 1996; Scholar). it is that potential binding are in the 5′-flanking sequence of a role in the c-IAP2 promoter stimulation remains to be In this the present of the 5′-flanking sequence of the c-IAP2 gene it to direct at a of the and involved in the or c-IAP2 gene in this study is that of CD40 or in the c-IAP2 gene activation. CD40 and are cell NF-κB activation the antiapoptotic proteins Bcl-2 and C.D. F. Dixit V.M. J. Biol. Chem. 1992; 267: Full Text PDF PubMed Google Scholar, S. M. C. D. F. R. A. Cell. Full Text PDF PubMed Scopus Google Scholar, V. Z. Clark L. M. Dixit V.M. J. Biol. Chem. 1995; Full Text Full Text PDF PubMed Scopus Google Scholar). with the that CD40 stimulation on B cells the level of c-IAP2 not the of other family members and (19.Craxton A. Shu G. Graves J.D. Saklatvala J. Krebs E.G. Clark E.A. J. Immunol. 1998; 161: 3225-3236PubMed Google Scholar), that CD40 activated the c-IAP2 promoter suggests that one mechanism by which CD40 cells apoptosis is via of results that an Epstein-Barr virus latent membrane protein for B cell expression of c-IAP2 In these it is that proteins are present in the cells in more of H. G. J. Res. PubMed Scopus Google Scholar) and that the level of c-IAP2 expression is in the cells C. M.H. R. A. J. Blood. 1998; 91: PubMed Google Scholar). of is that TRAF1 is to be in the cells and cells H. G. H. C. H. Blood. 1999; 93: PubMed Google Scholar). Furthermore, TRAF1 can be by in the B cell G. M. R. T. C. Cell. 1995; Full Text PDF PubMed Scopus Google Scholar), and its T apoptosis B. J. A. Y. J. Exp. Med. 1997; PubMed Scopus Google Scholar). TRAF1 is with the of apoptosis by TNF under the in which TRAF1, TRAF2, c-IAP-1, and c-IAP2 are all (17.Wang C.Y. Mayo M.W. Korneluk R.G. Goeddel D.V. Baldwin Jr., A.S. Science. 1998; 281: 1680-1683Crossref PubMed Scopus (2584) Google Scholar). it can be that the c-IAP2 protein as a or antiapoptotic factor in cell or such as with the or in with TRAF1 or other antiapoptotic proteins such as and are to the role of c-IAP2 in and in the the antiapoptotic protein c-IAP2 as a of NF-κB the expression of which is dependent on the of two NF-κB binding the found c-IAP2 to be by stimulation of a of cell IL-1 and which NF-κB activation. the present of the transcriptional mechanism of the c-IAP2 gene expression an of the that transcriptional activation of NF-κB on antiapoptotic genes is a mechanism involved in the or protective effect in response to various apoptotic also more on the role of c-IAP2 in tumor cell and