title: RelB is required for Peyer's patch development: differential regulation of p52-RelB by lymphotoxin and TNF.
abstract: Targeted disruption of the Rel/NF-kappaB family members NF-kappaB2, encoding p100/p52, and RelB in mice results in anatomical defects of secondary lymphoid tissues. Here, we report that development of Peyer's patch (PP)-organizing centers is impaired in both NF-kappaB2- and RelB-deficient animals. IL-7-induced expression of lymphotoxin (LT) in intestinal cells, a crucial step in PP development, is not impaired in RelB-deficient embryos. LTbeta receptor (LTbetaR)-deficient mice also lack PPs, and we demonstrate that LTbetaR signaling induces p52-RelB and classical p50-RelA heterodimers, while tumor necrosis factor (TNF) activates only RelA. LTbetaR-induced binding of p52-RelB requires the degradation of the inhibitory p52 precursor, p100, which is mediated by the NF-kappaB-inducing kinase (NIK) and the IkappaB kinase (IKK) complex subunit IKKalpha, but not IKKbeta or IKKgamma. Activation of RelA requires all three IKK subunits, but is independent of NIK. Finally, we show that TNF increases p100 levels, resulting in the specific inhibition of RelB DNA binding via the C-terminus of p100. Our data indicate an important role of p52-RelB heterodimers in lymphoid organ development downstream of LTbetaR, NIK and IKKalpha.
authors.affiliation: Forschungszentrum Karlsruhe, Institute of Toxicology and Genetics, D-76021 Karlsruhe, Germany.
authors.forename: Z Buket
authors.initials: ZB
authors.lastname: Yilmaz
authors.forename: Debra S
authors.initials: DS
authors.lastname: Weih
authors.forename: Vallabhapurapu
authors.initials: V
authors.lastname: Sivakumar
authors.forename: Falk
authors.initials: F
authors.lastname: Weih
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D002478:Cells, Cultured; D017931:DNA Primers; D005786:Gene Expression Regulation / Q000187:drug effects; D007413:Intestinal Mucosa / Q000196:embryology; D008233:Lymphotoxin-alpha / Q000494:pharmacology*; D051379:Mice; D018345:Mice, Knockout; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000172:deficiency / Q000235:genetics; D052003:NF-kappa B p52 Subunit; D010581:Peyer's Patches / Q000166:cytology*; D011518:Proto-Oncogene Proteins / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D051841:Transcription Factor RelB; D014157:Transcription Factors / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism*; D014158:Transcription, Genetic; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D017931:DNA Primers; D008233:Lymphotoxin-alpha; D016328:NF-kappa B; D052003:NF-kappa B p52 Subunit; D011518:Proto-Oncogene Proteins; C504650:Psip1 protein, mouse; D012333:RNA, Messenger; C497594:Relb protein, mouse; D015534:Trans-Activators; D014157:Transcription Factors; D014409:Tumor Necrosis Factor-alpha; D051841:Transcription Factor RelB