title: Structural relationship between the two IgY of the duck, Anas platyrhynchos: molecular genetic evidence.
abstract: cDNA clones encoding the H chains of the 7.8S and 5.7S IgY of the White Pekin duck have been isolated and sequenced. The H chain of the 7.8S IgY possesses four C region domains and thus resembles the H chain of chicken IgY with which it shows, in the C region, 54% inferred amino acid sequence identity, and complete conservation of the C region cysteine and tryptophan residues. The H chain of the 5.7S IgY possesses only two C region domains, that are virtually identical to CH1 and CH2 of the 7.8S IgY H chain. Although Southern blot genomic analysis did not resolve whether the two transcripts encoding the H chains of the 7.8S and 5.7S IgY are derived from one or two H chain-encoding genes, the CH 1, 2, 3, and 4 exons are apparently colinear, and no evidence was found for a separate locus in which CH1 and 2 exons were present and CH3 and 4 exons were lacking. The VH domain-encoding sequences of the cDNA for the two IgY H chains showed high similarity in the inferred VH gene (93% nucleotide and 91% inferred amino acid identity) and in the inferred JH segment (89% nucleotide and 93% inferred amino acid identity) but low similarity in the D region (26% nucleotide and 7% inferred amino acid identity). Genomic Southern blot hybridization analysis showed multiple VH-hybridizing sequences represented on up to 20 restriction fragments.
authors.affiliation: Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston 29425.
authors.forename: K E
authors.initials: KE
authors.lastname: Magor
authors.forename: G W
authors.initials: GW
authors.lastname: Warr
authors.forename: D
authors.initials: D
authors.lastname: Middleton
authors.forename: M R
authors.initials: MR
authors.lastname: Wilson
authors.forename: D A
authors.initials: DA
authors.lastname: Higgins
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002645:Chickens; D003001:Cloning, Molecular; D004372:Ducks / Q000235:genetics / Q000276:immunology*; D005803:Genes, Immunoglobulin; D007143:Immunoglobulin Heavy Chains / Q000235:genetics*; D007135:Immunoglobulin Variable Region / Q000235:genetics; D007136:Immunoglobulins / Q000235:genetics*; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000032:analysis
chemical_list: C016512:IgY; D007143:Immunoglobulin Heavy Chains; D007135:Immunoglobulin Variable Region; D007136:Immunoglobulins; D012333:RNA, Messenger