title: Double plant homeodomain (PHD) finger proteins DPF3a and -3b are required as transcriptional co-activators in SWI/SNF complex-dependent activation of NF-κB RelA/p50 heterodimer.
abstract: We have previously shown that DPF2 (requiem/REQ) functions as a linker protein between the SWI/SNF complex and RelB/p52 NF-κB heterodimer and plays important roles in NF-κB transactivation via its noncanonical pathway. Using sensitive 293FT reporter cell clones that had integrated a SWI/SNF-dependent NF-κB reporter gene, we find in this study that the overexpression of DPF1, DPF2, DPF3a, DPF3b, and PHF10 significantly potentiates the transactivating activity of typical NF-κB dimers. Knockdown analysis using 293FT reporter cells that endogenously express these five proteins at low levels clearly showed that DPF3a and DPF3b, which are produced from the DPF3 gene by alternative splicing, are the most critical for the RelA/p50 NF-κB heterodimer transactivation induced by TNF-α stimulation. Our data further show that this transactivation requires the SWI/SNF complex. DPF3a and DPF3b are additionally shown to interact directly with RelA, p50, and several subunits of the SWI/SNF complex in vitro and to be co-immunoprecipitated with RelA/p50 and the SWI/SNF complex from the nuclear fractions of cells treated with TNF-α. In ChIP experiments, we further found that endogenous DPF3a/b and the SWI/SNF complex are continuously present on HIV-1 LTR, whereas the kinetics of RelA/p50 recruitment after TNF-α treatment correlate well with the viral transcriptional activation levels. Additionally, re-ChIP experiments showed DPF3a/b and the SWI/SNF complex associate with RelA on the endogenous IL-6 promoter after TNF-α treatment. In conclusion, our present data indicate that by linking RelA/p50 to the SWI/SNF complex, DPF3a/b induces the transactivation of NF-κB target gene promoters in relatively inactive chromatin contexts.
authors.affiliation: Division of Host-Parasite Interaction, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan.
authors.forename: Aya
authors.initials: A
authors.lastname: Ishizaka
authors.forename: Taketoshi
authors.initials: T
authors.lastname: Mizutani
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Toshio
authors.initials: T
authors.lastname: Tando
authors.forename: Kouhei
authors.initials: K
authors.lastname: Sakurai
authors.forename: Toshinobu
authors.initials: T
authors.lastname: Fujiwara
authors.forename: Hideo
authors.initials: H
authors.lastname: Iba
mesh_terms: D001665:Binding Sites; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D042002:Chromatin Assembly and Disassembly; D047369:Chromatin Immunoprecipitation; D004268:DNA-Binding Proteins / Q000378:metabolism / Q000502:physiology*; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D006801:Humans; D007700:Kinetics; D008156:Luciferases / Q000096:biosynthesis / Q000235:genetics; D046912:Multiprotein Complexes / Q000378:metabolism; D052002:NF-kappa B p50 Subunit / Q000378:metabolism*; D011485:Protein Binding; D020033:Protein Isoforms / Q000378:metabolism / Q000502:physiology; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D020218:Response Elements; D051996:Transcription Factor RelA / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism / Q000502:physiology*; D015533:Transcriptional Activation; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism / Q000502:physiology
chemical_list: D004268:DNA-Binding Proteins; C452161:DPF3 protein, human; D046912:Multiprotein Complexes; D052002:NF-kappa B p50 Subunit; D020033:Protein Isoforms; C498143:RELA protein, human; D051996:Transcription Factor RelA; D014157:Transcription Factors; D014409:Tumor Necrosis Factor-alpha; D008156:Luciferases