title: Channel catfish, Ictalurus punctatus, CD4-like molecules.
abstract: Two CD4-like (CD4L) molecules have been identified in channel catfish, Ictalurus punctatus. Although phylogenetically related to other vertebrate CD4 molecules, they exhibit only 19% amino acid identity to each other. IpCD4L-1 encodes a predicted protein containing four immunoglobulin domains, a transmembrane region and a cytoplasmic tail containing a p56(lck) binding site. In contrast, IpCD4L-2 encodes for a similar protein with three immunoglobulin domains. The gene organization of IpCD4L-1 is very similar to that of other vertebrate CD4 genes, while the genomic organization of IpCD4L-2 is different. Southern blots indicate both catfish molecules are likely single copy genes and mapping studies show that both are found on a single Bacterial Artificial Chromosome suggesting close linkage. At the message level, IpCD4L-1 and -2 are expressed in various catfish lymphoid tissues and in non-B-cell peripheral blood leukocytes (PBL). Both messages are upregulated in concanavalin A (ConA) and alloantigen stimulated PBL, but not in lipopolysaccharide (LPS)-stimulated cultures. In contrast, they are differentially expressed among the catfish clonal T cell lines. While both molecules appear to be T cell specific, their functional significance in catfish is unknown.
authors.affiliation: Department of Microbiology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216, USA.
authors.forename: Eva-Stina
authors.initials: ES
authors.lastname: Edholm
authors.forename: James L
authors.initials: JL
authors.lastname: Stafford
authors.forename: Sylvie M
authors.initials: SM
authors.lastname: Quiniou
authors.forename: Geoff
authors.initials: G
authors.lastname: Waldbieser
authors.forename: Norman W
authors.initials: NW
authors.lastname: Miller
authors.forename: Eva
authors.initials: E
authors.lastname: Bengtén
authors.forename: Melanie
authors.initials: M
authors.lastname: Wilson
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015139:Blotting, Southern; D015704:CD4 Antigens / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D007059:Ictaluridae / Q000276:immunology*; D008969:Molecular Sequence Data; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology
chemical_list: D015704:CD4 Antigens