Abstract
Two selected receptor genes of the immunoglobulin superfamily (IgSF), one CTX/JAM family member, and one poliovirus receptor-like nectin that have features of adhesion molecules can be expressed by Ciona hemocytes, the effectors of immunity. They can also be expressed in the nervous system (CTX/JAM) and in the ovary (nectin). The genes encoding these receptors are located among one set of genes, spread over Ciona chromosomes 4 and 10, and containing other IgSF members homologous to those encoded by genes present in a tetrad of human (1, 3 + X, 11, 21 + 19q) or bird chromosomes (1, 4, 24, 31) that include the leukocyte receptor complex. It is proposed that this tetrad is due to the two rounds of duplication that affected a single prevertebrate ancestral region containing a primordial leukocyte receptor complex involved in immunity and other developmental regulatory functions.
MeSH terms
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Amino Acid Sequence
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Animals
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Cell Adhesion Molecules / genetics
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Chickens / genetics
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Chromosome Mapping
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Ciona intestinalis / embryology
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Ciona intestinalis / genetics
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Ciona intestinalis / growth & development
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Evolution, Molecular*
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Female
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Gene Expression Regulation, Developmental
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Hemocytes / metabolism
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Histocompatibility Antigens Class I / genetics
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In Situ Hybridization
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Junctional Adhesion Molecules
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Leukocytes / immunology
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Leukocytes / metabolism
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Male
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Molecular Sequence Data
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Nectins
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Phylogeny*
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Receptors, Immunologic / classification
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Receptors, Immunologic / genetics*
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Reverse Transcriptase Polymerase Chain Reaction
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Sequence Homology, Amino Acid
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Synteny
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Urochordata / embryology
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Urochordata / genetics
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Urochordata / growth & development
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Vertebrates / classification
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Vertebrates / genetics*
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Vertebrates / immunology
Substances
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Cell Adhesion Molecules
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Histocompatibility Antigens Class I
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Junctional Adhesion Molecules
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Nectins
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Receptors, Immunologic