title: Shark Ig light chain junctions are as diverse as in heavy chains.
abstract: We have characterized a small family of four genes encoding one of the three nurse shark Ig L chain isotypes, called NS5. All NS5 cDNA sequences are encoded by three loci, of which two are organized as conventional clusters, each consisting of a V and J gene segment that can recombine and one C region exon; the third contains a germline-joined VJ in-frame and the fourth locus is a pseudogene. This is the second nurse shark L chain type where both germline-joined and split V-J organizations have been found. Since there are only two rearranging Ig loci, it was possible for the first time to examine junctional diversity in defined fish Ig genes, comparing productive vs nonproductive rearrangements. N region addition was found to be considerably more extensive in length and in frequency than any other vertebrate L chain so far reported and rivals that in H chain. We put forth the speculation that the unprecedented efficiency of N region addition (87-93% of NS5 sequences) may be a result not only of simultaneous H and L chain rearrangement in the shark but also of processing events that afford greater accessibility of the V or J gene coding ends to terminal deoxynucleotidyltransferase.
authors.affiliation: Department of Physiology and Pharmacology, State University of New York Health Science Center, Brooklyn, NY 11203, USA.
authors.forename: Marshall
authors.initials: M
authors.lastname: Fleurant
authors.forename: Lily
authors.initials: L
authors.lastname: Changchien
authors.forename: Chin-Tung
authors.initials: CT
authors.lastname: Chen
authors.forename: Martin F
authors.initials: MF
authors.lastname: Flajnik
authors.forename: Ellen
authors.initials: E
authors.lastname: Hsu
mesh_terms: D024509:3' Flanking Region / Q000235:genetics; D024506:5' Flanking Region / Q000235:genetics; D000818:Animals; D000916:Antibody Diversity / Q000235:genetics; D001483:Base Sequence; D022801:Complementarity Determining Regions / Q000235:genetics; D015326:Gene Rearrangement, B-Lymphocyte, Heavy Chain; D015328:Gene Rearrangement, B-Lymphocyte, Light Chain; D005819:Genetic Markers / Q000276:immunology; D015698:Genomic Library; D007143:Immunoglobulin Heavy Chains / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D007132:Immunoglobulin Isotypes / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D007133:Immunoglobulin Joining Region / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D007147:Immunoglobulin Light Chains / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D012323:RNA Processing, Post-Transcriptional / Q000276:immunology; D012754:Sharks / Q000235:genetics / Q000276:immunology*; D013045:Species Specificity
chemical_list: D022801:Complementarity Determining Regions; D005819:Genetic Markers; D007143:Immunoglobulin Heavy Chains; D007132:Immunoglobulin Isotypes; D007133:Immunoglobulin Joining Region; D007147:Immunoglobulin Light Chains