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Title: Channel Catfish, Ictalurus punctatus Rafinesque 1818, Tetraspanin Membrane Protein Family: Characterization and Expression Analysis of CD81 cDNA

Author
item Yeh, Hung-Yueh
item Klesius, Phillip

Submitted to: Veterinary Immunology and Immunopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/26/2008
Publication Date: 3/5/2009
Citation: Yeh, H., Klesius, P.H. 2009. Channel catfish, Ictalurus punctatus Rafinesque 1818, tetraspanin membrane protein family: characterization and expression analysis of CD81 cDNA. Veterinary Immunology and Immunopathology. 128:431-436.

Interpretive Summary: Like human cells, channel catfish cells have various types of cell markers on the surface that play many important roles in biological processes. One of them is CD81, which is also known as the target of an antiproliferative antibody 1 (TAPA-1). CD81 is a member of tetraspanin integral membrane protein family. In this communication, we cloned, sequenced and characterized the channel catfish CD81 complimentary DNA (cDNA). The complete nucleic acid sequence of channel catfish CD81 cDNA comprised of 1,130 nucleotides, including an open reading frame, which appears to encode a putative peptide of 234 amino acid residues. By comparison with human CD81, the channel catfish CD81 peptide can be divided into domains, including four transmembrane regions, three intracellular regions, and one of each small and large extracellular loops. The channel catfish CD81 transcript was detected by RT-PCR in spleen, head kidney, liver, intestine, skin and gill. This result provides important information for further elucidating CD81 functions in channel catfish.

Technical Abstract: CD81, also known as the target of an antiproliferative antibody 1 (TAPA-1), is a member of tetraspanin integral membrane protein family. This protein plays many important roles in immune functions. In this report, we characterized and analyzed expression of the channel catfish CD81 transcript. The full-length of channel catfish CD81 cDNA comprised of 1,130 nucleotides, including an open reading frame in which appears to encode a putative peptide of 234 amino acid residues. By comparison with human counterpart, the channel catfish CD81 peptide could be divided into domains, including four transmembrane domains, three intracellular domains, and one of each small and large extracellular loops. The degree of conservation of the channel catfish CD81 amino acid sequence to mammalian counterparts ranged from 65 to 67%. The large extracellular domain shows the least conserved between fish and mammals. However, the characteristic Cys159-Cys160-Gly161 motif and Cys176/188 in this domain were conserved. The channel catfish CD81 transcript was detected by RT-PCR in spleen, head kidney, liver, intestine, skin and gill. This result provides important information for further elucidating CD81 functions in channel catfish.