Abstract
The bursa of Fabricius is a gut-associated lymphoid organ that is essential for the generation of a diversified B cell repertoire in the chicken. We describe here a novel gene preferentially expressed in bursal B cells. The gene encodes an 85-kDa protein, designated BASH (B cell adaptor containing SH2 domain), that contains N-terminal acidic domains with SH2 domain-binding phosphotyrosine-based motifs, a proline-rich domain, and a C-terminal SH2 domain. BASH shows a substantial sequence similarity to SLP-76, an adaptor protein functioning in TCR-signal transduction. BASH becomes tyrosine-phosphorylated with the B cell Ag receptor (BCR) cross-link or by coexpression with Syk and Lyn and associates with signaling molecules including Syk and a putative chicken Shc homologue. Overexpression of BASH results in suppression of the NF-AT activation induced by BCR-cross-linking. These findings suggest that BASH is involved in BCR-mediated signal transduction and could play a critical role in B cell development in the bursa.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adaptor Proteins, Signal Transducing*
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Adaptor Proteins, Vesicular Transport*
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Amino Acid Sequence
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Animals
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B-Lymphocytes / immunology
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B-Lymphocytes / metabolism*
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Bursa of Fabricius / cytology
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Bursa of Fabricius / immunology
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Bursa of Fabricius / metabolism*
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Carrier Proteins*
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Cell Line
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Chickens
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DNA, Complementary / isolation & purification
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DNA-Binding Proteins / metabolism
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Enzyme Precursors / metabolism
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Enzyme Precursors / physiology
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Humans
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Immunoglobulin M / metabolism
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Intracellular Signaling Peptides and Proteins
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Molecular Sequence Data
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NFATC Transcription Factors
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Nuclear Proteins*
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Phosphoproteins / biosynthesis*
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Phosphoproteins / genetics
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Phosphoproteins / metabolism
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Phosphorylation
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Protein-Tyrosine Kinases / metabolism
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Protein-Tyrosine Kinases / physiology
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Proteins / metabolism
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RNA, Messenger / biosynthesis
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Receptors, Antigen, B-Cell / metabolism
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Receptors, Antigen, B-Cell / physiology
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Shc Signaling Adaptor Proteins
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Signal Transduction / immunology*
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Src Homology 2 Domain-Containing, Transforming Protein 1
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Syk Kinase
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Transcription Factors / metabolism
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Tyrosine / metabolism
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src Homology Domains / immunology*
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src-Family Kinases / physiology
Substances
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Adaptor Proteins, Signal Transducing
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Adaptor Proteins, Vesicular Transport
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B cell linker protein
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Carrier Proteins
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DNA, Complementary
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DNA-Binding Proteins
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Enzyme Precursors
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Immunoglobulin M
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Intracellular Signaling Peptides and Proteins
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NFATC Transcription Factors
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Nuclear Proteins
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Phosphoproteins
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Proteins
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RNA, Messenger
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Receptors, Antigen, B-Cell
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SHC1 protein, human
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Shc Signaling Adaptor Proteins
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Src Homology 2 Domain-Containing, Transforming Protein 1
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Transcription Factors
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Tyrosine
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Protein-Tyrosine Kinases
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SYK protein, human
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Syk Kinase
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src-Family Kinases