Positive and Negative Regulation of Nuclear Factor-κB-mediated Transcription by IκB-ζ, an Inducible Nuclear Protein

IκB-ζ is an inducible nuclear protein that interacts with nuclear factor-κB (NF-κB) via its carboxyl-terminal ankyrin-repeats. Previous studies using an NF-κB reporter have shown that IκB-ζ inhibits the activity of NF-κB. In the present study, we dissected the amino-terminal region of IκB-ζ, which shows no homology to any other proteins. Indirect immunofluorescence studies demonstrated the presence of a bipartite nuclear localization signal spanning amino acids 163–178. Using GAL4 fusion proteins, we found that internal fragments containing amino acids 329–402 possessed intrinsic transcriptional activation activity. Interestingly, the activity was not detected in GAL4 fusion proteins of the full-length IκB-ζ. On the other hand, the GAL4-dependent transcriptional activity was generated by co-expression of the GAL4-NF-κB p50 subunit fusion protein and the full-length IκB-ζ, neither of which exhibited the activity on their own. A new splicing variant, IκB-ζ(D), with a deletion of amino acids 236–429, was found to lack transactivation activity. Forced expression of IκB-ζ, but not IκB-ζ(D), augmented interleukin-6 production, indicating the functional significance of the transactivation activity. In contrast, tumor necrosis factor-α production was inhibited by expression of IκB-ζ, highlighting the dual functions of this molecule. These results indicate that IκB-ζ harbors latent transcriptional activation activity, and that the activity is expressed upon interaction with the NF-κB p50 subunit. In addition to the inhibitory activity on NF-κB-mediated transcription, the transcriptional activation activity of IκB-ζ should be crucial for the regulation of inflammation. IκB-ζ is an inducible nuclear protein that interacts with nuclear factor-κB (NF-κB) via its carboxyl-terminal ankyrin-repeats. Previous studies using an NF-κB reporter have shown that IκB-ζ inhibits the activity of NF-κB. In the present study, we dissected the amino-terminal region of IκB-ζ, which shows no homology to any other proteins. Indirect immunofluorescence studies demonstrated the presence of a bipartite nuclear localization signal spanning amino acids 163–178. Using GAL4 fusion proteins, we found that internal fragments containing amino acids 329–402 possessed intrinsic transcriptional activation activity. Interestingly, the activity was not detected in GAL4 fusion proteins of the full-length IκB-ζ. On the other hand, the GAL4-dependent transcriptional activity was generated by co-expression of the GAL4-NF-κB p50 subunit fusion protein and the full-length IκB-ζ, neither of which exhibited the activity on their own. A new splicing variant, IκB-ζ(D), with a deletion of amino acids 236–429, was found to lack transactivation activity. Forced expression of IκB-ζ, but not IκB-ζ(D), augmented interleukin-6 production, indicating the functional significance of the transactivation activity. In contrast, tumor necrosis factor-α production was inhibited by expression of IκB-ζ, highlighting the dual functions of this molecule. These results indicate that IκB-ζ harbors latent transcriptional activation activity, and that the activity is expressed upon interaction with the NF-κB p50 subunit. In addition to the inhibitory activity on NF-κB-mediated transcription, the transcriptional activation activity of IκB-ζ should be crucial for the regulation of inflammation. A wide variety of cellular activities are executed by the coordinated expression of diverse genes. Precise regulation of the transcription factors that control gene expression is vital to accomplish specific tasks as well as to maintain life. Various endogenous and exogenous stimuli induce alterations of the gene expression profiles, and dynamic changes of the profiles are observed in immune responses to microbial infections, an essential reaction for the survival of multicellular organisms. Innate and adaptive immune systems function cooperatively in vertebrate animals for defense against infection by various pathogens (1Akira S. Takeda K. Kaisho T. Nat. Immunol. 2001; 2: 675-680Crossref PubMed Scopus (3910) Google Scholar, 2Hoebe K. Janssen E. Beutler B. Nat. Immunol. 2004; 5: 971-974Crossref PubMed Scopus (685) Google Scholar, 3Iwasaki A. Medzhitov R. Nat. Immunol. 2004; 5: 987-995Crossref PubMed Scopus (3299) Google Scholar). The transcription factor nuclear factor-κB (NF-κB) 1The abbreviations used are: NF-κB, nuclear factor-κB; RHD, Rel homology domain; TAD, transactivation domain; NLS, nuclear localization signal; LPS, lipopolysaccharide; IL, interleukin; TNF, tumor necrosis factor; RT, reverse transcription.1The abbreviations used are: NF-κB, nuclear factor-κB; RHD, Rel homology domain; TAD, transactivation domain; NLS, nuclear localization signal; LPS, lipopolysaccharide; IL, interleukin; TNF, tumor necrosis factor; RT, reverse transcription. plays pivotal roles in the activation of both immune systems (4Bonizzi G. Karin M. Trends Immunol. 2004; 25: 280-288Abstract Full Text Full Text PDF PubMed Scopus (2067) Google Scholar). This evolutionarily conserved transcription factor was initially identified as a nuclear factor that binds to the enhancer region of the immunoglobulin κ light chain (5Sen R. Baltimore D. Cell. 1986; 46: 705-716Abstract Full Text PDF PubMed Scopus (1924) Google Scholar), and is now known to be a ubiquitous and central transcription factor involved in a wide variety of important and diverse biological processes, including inflammation, cell proliferation, apoptosis, and cell differentiation (6Ghosh S. May M.J. Kopp E.B. Annu. Rev. Immunol. 1998; 16: 225-260Crossref PubMed Scopus (4585) Google Scholar, 7Karin M. Ben-Neriah Y. Annu. Rev. Immunol. 2000; 18: 621-663Crossref PubMed Scopus (4058) Google Scholar). NF-κB proteins exist as homo- or heterodimers of 5 kinds of subunits containing the Rel homology domain (RHD), which is involved in DNA binding and dimerization. p65 (RelA), c-Rel, and RelB contain a transcriptional activation domain (or transactivation domain, TAD) after the RHD. On the other hand, the p50 and p52 subunits, generated by processing of their larger precursors, namely p105 and p100, respectively, consist of the RHD alone without the TAD. The 5 different subunits produce at least 12 different combinations of NF-κBs. Among these, homo- or heterodimers of p50 and p52 are devoid of transcriptional activity and act as inhibitors of NF-κB-mediated transcription (6Ghosh S. May M.J. Kopp E.B. Annu. Rev. Immunol. 1998; 16: 225-260Crossref PubMed Scopus (4585) Google Scholar, 7Karin M. Ben-Neriah Y. Annu. Rev. Immunol. 2000; 18: 621-663Crossref PubMed Scopus (4058) Google Scholar). In quiescent cells, NF-κB is tethered to the cytoplasm as a complex with its inhibitor proteins, IκB-α, -β, and -ϵ (8Davis N. Ghosh S. Simmons D.L. Tempst P. Liou H.C. Baltimore D. Bose Jr., H.R. Science. 1991; 253: 1268-1271Crossref PubMed Scopus (156) Google Scholar, 9Haskill S. Beg A.A. Tompkins S.M. Morris J.S. Yurochko A.D. Sampson-Johannes A. Mondal K. Ralph P. Baldwin Jr., A.S. Cell. 1991; 65: 1281-1289Abstract Full Text PDF PubMed Scopus (586) Google Scholar, 10Thompson J.E. Phillips R.J. Erdjument-Bromage H. Tempst P. Ghosh S. Cell. 1995; 80: 573-582Abstract Full Text PDF PubMed Scopus (692) Google Scholar, 11Whiteside S.T. Epinat J.C. Rice N.R. Israel A. EMBO J. 1997; 16: 1413-1426Crossref PubMed Scopus (338) Google Scholar). The ankyrin-repeat motifs of the IκB proteins interact with the RHD of the NF-κB subunits to mask the nuclear localization signal (NLS). Exposure of cells to various stimuli including various microbial products, such as lipopolysaccharide (LPS), proinflammatory cytokines, T- and B-cell mitogens, as well as physical and chemical stresses, induces site-specific phosphorylation of IκBs, leading to ubiquitination followed by proteasome-mediated degradation (6Ghosh S. May M.J. Kopp E.B. Annu. Rev. Immunol. 1998; 16: 225-260Crossref PubMed Scopus (4585) Google Scholar). Consequently, liberated NF-κB translocates into the nucleus to drive the transcription of many target genes. Rapid activation of NF-κB without de novo synthesis of new proteins renders this transcription factor ideal for mediating primary cellular responses. Because uncontrolled activation of NF-κB, which is often observed with severe infections, leads to life-threatening symptoms represented by septic shock, the activity of NF-κB is tightly regulated in normal cells. Upon activation of NF-κB, cytosolic IκB-α is degraded, but transcription of IκB-α is up-regulated (12Brown K. Park S. Kanno T. Franzoso G. Siebenlist U. U. S. A. PubMed Scopus Google Scholar, Science. PubMed Scopus Google Scholar, R. B. E. H. EMBO J. PubMed Scopus Google Scholar, T. Liou H.C. Baltimore D. PubMed Scopus Google Scholar). IκB-α binds to NF-κB in the nucleus to into the cytoplasm and the activation of NF-κB N. M. S. U. S. A. 2000; PubMed Scopus Google Scholar, A. P. E. de R. J. Full Text Full Text PDF PubMed Scopus Google Scholar). NF-κB target such as Jr., J. Full Text PDF PubMed Google Scholar, D.L. S. M. A. Science. 2000; PubMed Scopus Google and the transcription factor D. K. Cell. Full Text Full Text PDF PubMed Scopus Google Scholar), have to the leading to NF-κB activation and the transcriptional activity of NF-κB, D. K. Cell. Full Text Full Text PDF PubMed Scopus Google Scholar). The NF-κB-mediated of their to expression of NF-κB activity. for roles for inducible proteins upon inflammation, we and identified an protein that was in to S. T. K. J. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar, H. K. K. M. M. 2000; PubMed Scopus Google Scholar, H. A. K. J. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar). This IκB-ζ, is in cells, but is not by but other microbial that S. T. K. J. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar, A. T. S. K. PubMed Scopus Google Scholar, M. S. S. S. H. K. Kaisho T. H. K. T. S. N. S. T. Takeda K. S. 2004; PubMed Scopus Google Scholar). The is observed upon by but not by proinflammatory tumor necrosis factor S. T. K. J. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar, H. A. K. J. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar). NF-κB activation is but not for the of IκB-ζ, and specific is for the S. T. K. J. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar, A. T. S. K. PubMed Scopus Google Scholar, S. T. S. K. J. Full Text Full Text PDF PubMed Scopus Google Scholar, K. T. K. PubMed Scopus Google Scholar). IκB-ζ are generated by splicing S. T. K. J. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar, H. K. K. M. M. 2000; PubMed Scopus Google Scholar, H. A. K. J. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar, T. M. H. T. S. K. Y. M. B. 2001; PubMed Scopus Google Scholar). The is upon S. T. S. K. J. Full Text Full Text PDF PubMed Scopus Google Scholar), and the the amino-terminal amino acids of of IκB-ζ in the carboxyl-terminal as observed in other IκB proteins. On the other hand, the amino-terminal of no homology to any other known proteins. In to the cytosolic and expressed IκB proteins, IκB-ζ is in the binds to the NF-κB p50 the p65 without of their nuclear S. T. K. J. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar). of IκB-ζ by reporter that inhibits the activity of NF-κB S. T. K. J. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar). In that the carboxyl-terminal domain with the inhibits the DNA binding of the as well as the p50 S. T. K. J. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar). an shown to be the functions of the IκB-ζ amino-terminal which of amino acids and is to IκB-ζ, to the functions of the amino-terminal we found that a in this region transcriptional activation activity. we that of IκB-ζ results in of production in to LPS, but inhibits These are with an essential for IκB-ζ in the of and other as by of the in which production by or cells is indicate that IκB-ζ is of the of NF-κB, which dual functions on the target genes. and in containing and and and by DNA fragments by into or with or without an amino-terminal was by of and and and The reporter containing a with 5 of the GAL4 binding and the internal control reporter and Various of IκB-ζ by was used as an NF-κB reporter T. K. J. 2001; PubMed Scopus Google Scholar). or cells on with the expression using after the cells with with and with an in containing the cells with and with using a reporter as cells with the expression with the GAL4 reporter and the internal control by the H. Cell. PubMed Scopus Google Scholar). after the cells and the activities using the NF-κB reporter using as the NF-κB reporter as T. K. J. 2001; PubMed Scopus Google Scholar). The activities the GAL4 or NF-κB by the activities of the internal control reporter cells or with for and was using to the of the was using an and reverse was on the using and reverse for of for for and for using the cells and the of to a S. T. T. 2000; PubMed Scopus Google Scholar). by of cells with namely the the and and a of as H. U. M. J. 1998; PubMed Google Scholar, T. K. Park M. K. A. Nat. PubMed Scopus Google Scholar). by was with reverse using DNA and a The used and for and and for of of and in the using systems and and with containing and inhibitor The cell by and to with The by to a and with a The amino-terminal region of IκB-ζ shows no homology to any other known proteins and is to the of the functional the amino we deletion at the for the of IκB-ζ, that the functional be of combinations of by we to an NLS, which we shown to be present in the amino-terminal region S. T. K. J. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar). Because is the expressed in cells S. T. S. K. J. Full Text Full Text PDF PubMed Scopus Google Scholar), this was to the and the amino used in the to that of The full-length and deletion of IκB-ζ into cells and their by with an In to IκB-α the cells, full-length IκB-ζ was in the as S. T. K. J. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar). A with a deletion the amino exhibited the nuclear localization as the full-length IκB-ζ. On the other hand, the with a deletion and a deletion not in the nucleus but the cells, indicating the presence of an in the region amino acids and with a of the to the not This region by and amino acids the at the of on amino acids and of to of at and the nuclear localization and the the cells. In contrast, of not nuclear These results indicate that and are for the nuclear localization of IκB-ζ, is amino acids the bipartite of IκB-ζ. A fusion protein containing amino acids nuclear localization not that this region alone is to function as an the of IκB-ζ was identified in a the functions of of the amino-terminal region of IκB-ζ A amino-terminal region of the IκB proteins, such as IκB-α, harbors a for phosphorylation and ubiquitination M. Ben-Neriah Y. Annu. Rev. Immunol. 2000; 18: 621-663Crossref PubMed Scopus (4058) Google Scholar). no such is present in the amino-terminal region of IκB-ζ. A the of IκB-ζ is of the of p105 and p100, the of the NF-κB p50 and p52 subunits, This to this region is involved in transcriptional to the for the NF-κB Because was not known IκB-ζ DNA binding activity, IκB-ζ and its fragments expressed as fusion proteins with the DNA binding domain of the transcription factor GAL4 and their transcriptional activation activities using a reporter containing a with the GAL4 binding of IκB-ζ the amino and expressed as GAL4 fusion proteins in cells and the reporter activities the GAL4 reporter The amino-terminal and as well as the full-length IκB-ζ which the not any activity the the of the amino to amino exhibited activity. the amino and this activity. The lack of the activities of the are not of expression as by using an These results indicate that the region amino acids and harbors a domain with transcriptional activation activity and that the activity is by the carboxyl-terminal ankyrin-repeats. that the activity observed in the was of be observed with the In we with IκB-ζ. GAL4 fusion proteins with amino acids and to the amino-terminal of and respectively, exhibited activity. the full-length and as well as the carboxyl-terminal not any activity their the observed with IκB-ζ conserved with IκB-ζ, indicating that transcriptional activation activity is to the of the IκB-ζ of the the internal region of amino acids by was expressed as a GAL4 fusion protein exhibited transactivation activity. deletion and their activities to this region be to a functional of the amino-terminal amino acids the activity, indicating that are of a amino acids the activity, but the activity observed was On the other hand, to amino the activity without the expression indicating an for amino acids this a GAL4 fusion protein with amino acids the activity, a with amino acids the internal fragments of IκB-ζ exhibited intrinsic transcriptional activation activity, the activity was not expressed by the GAL4 fusion protein with the full-length IκB-ζ. The shown in that the carboxyl-terminal domain containing the a in the activity. that IκB-ζ be to by interaction with a to the studies that the carboxyl-terminal domain containing the interacts with the NF-κB p50 subunit S. T. K. J. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar). we GAL4 fusion proteins of the p50 subunit and the or of IκB-ζ to the transcriptional activities of their on a GAL4-dependent the GAL4 fusion protein of the NF-κB p50 subunit alone not any activity, not have a TAD. of the full-length IκB-ζ in activity observed with the amino-terminal amino acids and but not with the amino an essential for the region amino acids and The amino-terminal containing amino acids not any activity in this indicating a for the carboxyl-terminal ankyrin-repeat which interacts with the p50 subunit. the complex of the NF-κB p50 subunit and IκB-ζ transcriptional activation activity. the NF-κB p50 subunit be with the p65 subunit. The p65 subunit transactivation activity, which was not by co-expression of IκB-ζ not we the carboxyl-terminal of the p65 subunit J. 1995; Full Text Full Text PDF PubMed Scopus Google and expressed the as a GAL4 fusion protein this fusion protein alone not any transactivation activity, but co-expression of IκB-ζ or of the deletion in the of transcriptional activity. The results with the p65 subunit fusion protein with the p50 that the RHD of p65 for the p50 subunit. the of this study, we found a for a splicing of IκB-ζ as in the This a deletion of amino acids which to the central of the domain with the transcriptional activation activity. Because we not a in the we a was present in was using a to the region by acids the that a of IκB-ζ in cells was using cells as a exhibited that the larger was the IκB-ζ, the of the internal in the deletion of amino acids The was observed in cells not indicating that its expression is not The of the fragments the conserved at the this splicing of a is upon which we Because this of the TAD, we its neither the amino-terminal the internal fragments transactivation activity expressed as GAL4 fusion proteins with this co-expression of the or fusion proteins with not to any transactivation activity its expression On the other hand, NF-κB reporter that the inhibitory activity NF-κB in cells, which was the and of IκB-ζ Because the transcriptional activation activity of IκB-ζ in systems using GAL4 fusion proteins and a GAL4 we to of that IκB-ζ is essential for the of and other in and upon with or M. S. S. S. H. K. Kaisho T. H. K. T. S. N. S. T. Takeda K. S. 2004; PubMed Scopus Google Scholar). H. K. K. M. M. 2000; PubMed Scopus Google that of which is to IκB-ζ, production in cells. we the of IκB-ζ expression on production in cells with or The cells or with LPS, and the into the was by production in or cells was augmented with that in control cells with an which is with the by H. K. K. M. M. 2000; PubMed Scopus Google Scholar). production was observed in the or cells. The was at the of by of in cells with the that IκB-ζ production at the transcriptional On the other hand, infection with the on This was not of a lack of that the expression of was to that of and that of with the NF-κB IκB-ζ inhibited NF-κB and S. T. K. J. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar), the as well as studies with gene M. S. S. S. H. K. Kaisho T. H. K. T. S. N. S. T. Takeda K. S. 2004; PubMed Scopus Google have that IκB-ζ functions in transcriptional the inhibitory of IκB-ζ on NF-κB was an of the reporter or this on the target we the of IκB-ζ expression on an gene other IκB-ζ into the cell using the and the of and proinflammatory Forced expression of IκB-ζ of production in cells, but augmented production in cells upon as was observed in cells. In to the on production, production was inhibited by expression of IκB-ζ These results of IκB-ζ on the expression of different genes. In the present study, we that IκB-ζ harbors intrinsic transcriptional activation activity, using the GAL4 reporter This is not the expression of the different GAL4 fusion proteins not with an that the lack of activity of the fusion proteins was not by their of various an for the region amino acids in the transcriptional activation activity. This not any activity expressed as a GAL4 fusion a for as a The of the fragments that transactivation activity shows no homology to any other proteins S. T. K. J. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar, H. K. K. M. M. 2000; PubMed Scopus Google Scholar, H. A. K. J. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar). the region is in and which are of the transcriptional activation of transcription including R. Cell. Full Text PDF PubMed Scopus Google and K. PubMed Scopus Google Scholar). the of IκB-ζ be by its of as an TAD, by its R. Science. PubMed Scopus Google Scholar). In we into this of the transactivation activity. In with other of IκB-ζ, the of this region is conserved and and in IκB-ζ(D), a of this region is as an is to that IκB-ζ a IκB protein a by the that is in to the TAD. The functional significance of the in the of IκB-ζ was by the of the splicing This a deletion in the expressed neither transactivation activity in GAL4 reporter of production, the activity. to the full-length for IκB-ζ was using cells, a for or was and a for was not that the a in cells. the of the splicing in and that this of NF-κB activity without transactivation activity a in the regulation of or other NF-κB-mediated is that the GAL4 fusion protein of the full-length IκB-ζ not transactivation activity. of other that the carboxyl-terminal the transactivation activity of the TAD. with the processing of p105 to the NF-κB p50 that the carboxyl-terminal region the transactivation activity of IκB-ζ T. 1991; PubMed Scopus Google Scholar, T. Cell. Full Text PDF PubMed Scopus Google Scholar). such processing not observed in S. T. S. K. J. Full Text Full Text PDF PubMed Scopus Google Scholar). the with the subunit fusion protein that complex with NF-κB subunits the transactivation activity of IκB-ζ. The functional significance of the complex was by the lack of activity observed with the amino-terminal containing the without the the interaction of the p50 subunit S. T. K. J. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar). The interaction of the p50 subunit with the of IκB-ζ an interaction via the carboxyl-terminal domain that the transcriptional activation activity, in of the in the of the molecule. that of IκB-ζ alone production in which was by Because the NF-κB p50 subunit shown to be essential for transcriptional activation by using p50 cells M. S. S. S. H. K. Kaisho T. H. K. T. S. N. S. T. Takeda K. S. 2004; PubMed Scopus Google Scholar), the activity is IκB-ζ interaction with nuclear p50 present in cells. of IκB-ζ exhibited on the production of different cytokines, and The activities of IκB-ζ on the different the of a specific or in the of IκB-ζ. Because NF-κB and its binding in the region have shown to be essential for S. T. T. T. J. Immunol. Google Scholar, U. P. Cell. PubMed Scopus Google and we not any DNA binding activity of IκB-ζ, is that the DNA binding activity of the complex is the NF-κB subunit. studies with a reporter containing a NF-κB that IκB-ζ inhibits the transcriptional activity of NF-κB, by the binding of NF-κB to this S. T. K. J. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar). The binding of NF-κB to IκB-ζ induce a in NF-κB that results in of the of the binding or with should be that the transactivation activities observed with the GAL4 fusion protein of IκB-ζ or the of the subunit and IκB-ζ observed with the GAL4 fusion protein of p65 or the of p65 not These that a in addition to the NF-κB p50 subunit is for transcription. a be to via a specific or a The of IκB-ζ are to to IκB-α, -β, and -ϵ S. T. K. J. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar). the cytosolic IκB proteins, with NF-κB p50 or p52 subunits in the which are T. K. Liou H.C. Baltimore D. Cell. PubMed Google Scholar). to NF-κB-mediated transcription by a complex with the p50 subunit T. K. Liou H.C. Baltimore D. Cell. PubMed Google Scholar, G. Park S. M. K. Siebenlist U. PubMed Scopus Google Scholar, G. Park S. M. Kanno T. K. Siebenlist U. EMBO J. PubMed Scopus Google Scholar), the complex of and the p52 subunit transcription Franzoso G. Park S. Kanno T. K. Siebenlist U. Cell. 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The the inhibitory activity of IκB-ζ using cells and cells that regulation of NF-κB is by including IκB-ζ, in to the essential for IκB-ζ in transcriptional the inhibitory activity of IκB-ζ to be essential in to maintain the of NF-κB-mediated gene as by the of in upon with M. S. S. S. H. K. Kaisho T. H. K. T. S. N. S. T. Takeda K. S. 2004; PubMed Scopus Google Scholar). studies on the of transcriptional regulation on the regulation of by this transcriptional to of and for for infections, and for on are to and for with