title: Identification and characterization of TCRγ and TCRδ chains in channel catfish, Ictalurus punctatus.
abstract: Channel catfish, Ictalurus punctatus, T cell receptors (TCR) γ and δ were identified by mining of expressed sequence tag databases, and full-length sequences were obtained by 5'-RACE and RT-PCR protocols. cDNAs for each of these TCR chains encode typical variable (V), diversity (D), joining (J), and constant (C) regions. Three TCRγ V families, seven TCRγ J sequences, and three TCRγ C sequences were identified from sequencing of cDNA. Primer walking on bacterial artificial chromosomes (BACs) confirmed that the TRG locus contained seven TRGJ segments and indicated that the locus consists of (Vγ3-Jγ6-Cγ2)-(Vγ1n-Jγ7-Cγ3)-(Vγ2-Jγ5-Jγ4-Jγ3-Jγ2-Jγ1-Cγ1). In comparison for TCRδ, two V families, four TCRδ D sequences, one TCRδ J sequence, and one TCRδ C sequence were identified by cDNA sequencing. Importantly, the finding that some catfish TCRδ cDNAs contain TCR Vα-D-Jδ rearrangements and some TCRα cDNAs contain Vδ-Jα rearrangements strongly implies that the catfish TRA and TRD loci are linked. Finally, primer walking on BACs and Southern blotting suggest that catfish have four TRDD gene segments and a single TRDJ and TRDC gene. As in most vertebrates, all three reading frames of each of the catfish TRDD segments can be used in functional rearrangements, and more than one TRDD segment can be used in a single rearrangement. As expected, catfish TCRδ CDR3 regions are longer and more diverse than TCRγ CDR3 regions, and as a group they utilize more nucleotide additions and contain more nucleotide deletions than catfish TCRγ rearrangements.
authors.affiliation: Department of Microbiology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216-4505, USA.
authors.forename: Mohadetheh
authors.initials: M
authors.lastname: Moulana
authors.forename: Erin B
authors.initials: EB
authors.lastname: Taylor
authors.forename: Eva-Stina
authors.initials: ES
authors.lastname: Edholm
authors.forename: Sylvie M A
authors.initials: SM
authors.lastname: Quiniou
authors.forename: Melanie
authors.initials: M
authors.lastname: Wilson
authors.forename: Eva
authors.initials: E
authors.lastname: Bengtén
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015139:Blotting, Southern; D018076:DNA, Complementary / Q000235:genetics; D020224:Expressed Sequence Tags; D007059:Ictaluridae / Q000235:genetics*; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid
chemical_list: D018076:DNA, Complementary; D012333:RNA, Messenger; D016692:Receptors, Antigen, T-Cell, gamma-delta