Abstract
Mice deficient in the RelA (p65) subunit of NF-kappaB die during embryonic development. Fetal liver (FL) hemopoietic precursors from these mice were used to generate RelA-deficient lymphocytes by adoptive transfer into lethally irradiated mature lymphocyte-deficient recombination-activating gene-1(-/-) mice. Strikingly, RelA(-/-) lymphocyte generation was greatly diminished compared with that of RelA(+/+) lymphocytes. The most dramatic reduction was noticed in the numbers of developing B cells, which were considerably increased when RelA(-/-) FL cells that were also TNFR1 deficient were used. The role of RelA was further investigated in FL-derived developing B cells in vitro. Our results show that RelA is a major component of constitutive and TNF-alpha-induced kappaB site-binding activity in developing B cells, and provide evidence for a direct role of TNF-alpha in killing RelA(-/-) B cells. The absence of RelA significantly reduced mRNA expression of the antiapoptotic genes cellular FLICE-inhibitory protein and Bcl-2. Retroviral transduction of RelA(-/-) B cells with either cFLIP or Bcl-2 significantly reduced TNF-alpha killing. Together, these results indicate that RelA plays a crucial role in regulating developing B cell survival by inhibiting TNF-alpha cytotoxicity.
Publication types
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Animals
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Antigens, CD / genetics
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Antigens, CD / physiology
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Apoptosis / genetics
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Apoptosis / immunology
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B-Lymphocyte Subsets / cytology*
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B-Lymphocyte Subsets / immunology
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B-Lymphocyte Subsets / metabolism*
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Binding Sites / genetics
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Binding Sites / immunology
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CASP8 and FADD-Like Apoptosis Regulating Protein
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Carrier Proteins / antagonists & inhibitors
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Carrier Proteins / biosynthesis
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Carrier Proteins / physiology
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Cell Differentiation / genetics
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Cell Differentiation / immunology
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Cell Survival / genetics
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Cell Survival / immunology
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Cells, Cultured
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Cytotoxicity, Immunologic / genetics
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Genetic Vectors
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Homeodomain Proteins / genetics
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Intracellular Signaling Peptides and Proteins*
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Mice
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Mice, Knockout
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NF-kappa B / deficiency
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NF-kappa B / genetics
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NF-kappa B / metabolism
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NF-kappa B / physiology*
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Protein Subunits / deficiency
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Protein Subunits / genetics
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Protein Subunits / physiology*
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Proto-Oncogene Proteins c-bcl-2 / antagonists & inhibitors
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Proto-Oncogene Proteins c-bcl-2 / biosynthesis
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Proto-Oncogene Proteins c-bcl-2 / physiology
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Receptors, Tumor Necrosis Factor / deficiency
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Receptors, Tumor Necrosis Factor / genetics
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Receptors, Tumor Necrosis Factor / physiology
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Receptors, Tumor Necrosis Factor, Type I
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Retroviridae / genetics
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Transcription Factor RelA
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Tumor Necrosis Factor-alpha / antagonists & inhibitors
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Tumor Necrosis Factor-alpha / toxicity
Substances
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Antigens, CD
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CASP8 and FADD-Like Apoptosis Regulating Protein
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Carrier Proteins
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Cflar protein, mouse
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Homeodomain Proteins
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Intracellular Signaling Peptides and Proteins
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NF-kappa B
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Protein Subunits
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Proto-Oncogene Proteins c-bcl-2
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Receptors, Tumor Necrosis Factor
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Receptors, Tumor Necrosis Factor, Type I
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Transcription Factor RelA
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Tumor Necrosis Factor-alpha
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RAG-1 protein