title: Characterisation of a fourth immunoglobulin light chain isotype in the common carp.
abstract: Three isotypes of immunoglobulin (Ig) light (L) chain, designated L1A, L1B, and L3, have been characterised in the common carp (Cyprinus carpio L.) to date. In this paper the molecular cloning of a fourth IgL isotype in carp, designated L2, is described. A reverse transcription-polymerase chain reaction (RT-PCR) method including 5'- and 3'-RACE was used to isolate carp L2 cDNA clones. The VL sequences could be divided into two distinct VL families, designated VL2-1 and VL2-2, most similar to rainbow trout (68% similarity) and zebrafish (78%) VL2 amino acid sequences, respectively. The CL amino acid sequences showed the highest similarity to zebrafish L2 (80%), and contained the characteristic cysteines necessary for intradomain or interchain disulphide bridges as did the VL sequences. Neither the VL nor CL sequences demonstrated such a high similarity to the other carp IgL isotypes, L1A, L1B, and L3. For JL segments, sequence variations appeared to be confined to a few positions. In the course of 5'- and 3'-RACE, cDNA clones containing recombination signal sequence (RSS), representatives of IgL sterile transcripts, were obtained. Southern blot analyses suggested that the locus of carp L2 has a cluster-like organisation. Phylogenetic analyses showed that both carp VL2 and CL2 amino acid sequences highly clustered with other teleost L2 sequences.
authors.affiliation: Department of Applied Biological Science, Nihon University, 1866 Kameino, Fujisawa, Kanagawa 252-8510, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Ishikawa
authors.forename: Etsuou
authors.initials: E
authors.lastname: Imai
authors.forename: Tadaaki
authors.initials: T
authors.lastname: Moritomo
authors.forename: Miki
authors.initials: M
authors.lastname: Nakao
authors.forename: Tomoki
authors.initials: T
authors.lastname: Yano
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Tomana
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015139:Blotting, Southern; D002347:Carps / Q000235:genetics* / Q000276:immunology*; D016000:Cluster Analysis; D017931:DNA Primers; D018076:DNA, Complementary / Q000235:genetics; D007132:Immunoglobulin Isotypes / Q000235:genetics*; D007147:Immunoglobulin Light Chains / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D017385:Sequence Homology
chemical_list: D017931:DNA Primers; D018076:DNA, Complementary; D007132:Immunoglobulin Isotypes; D007147:Immunoglobulin Light Chains