title: Novel TAP1 polymorphisms in indigenous Zimbabweans: their potential implications on TAP function and in human diseases.
abstract: Because of the essential role of transporter associated with antigen processing (TAP1 or TAP2) molecule in antigen processing, the implication of its polymorphism as a factor involved in human diseases and the possible genetic variation at this locus among ethnically diverse populations, we underwent a study to analyze the full extent of TAP1 polymorphism in an indigenous Zimbabwean population (Shona ethnic group). Using single-stranded conformation polymorphism and DNA direct sequencing procedures, we detected the presence of 11 nucleotide sequence variations in the entire coding region of TAP1. Of these variants, eight are nonconservative substitutions with respect to amino acid composition and are located in a critical part of the protein that could modulate its function. Five new polymorphic sites were identified in exon 1 (codons 7 Pro --> Ser, 17 Gly --> Arg, 141 Val --> Val), exon 6 (codon 419 Gly --> Cys), and exon 7 (codon 487 Arg --> Arg). Significant differences were seen in the distribution of TAP1*0201 and TAP1*0401 alleles, and codon 333 (Ile --> Val) polymorphism among African and non-African populations. Thus, TAP1 polymorphism has evolved differently among populations presumably because of the evolutionary pressures generated by prevalent pathogens in these geographically distinct regions.
authors.affiliation: Laboratoire d'Immunogénétique, Centre de Recherche du Centre Hospitalier, de l'Université de Montréal, Montréal, Québec, Canada.
authors.forename: Julie
authors.initials: J
authors.lastname: Lajoie
authors.forename: Lynn S
authors.initials: LS
authors.lastname: Zijenah
authors.forename: Marie Claude
authors.initials: MC
authors.lastname: Faucher
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Ward
authors.forename: Michel
authors.initials: M
authors.lastname: Roger
mesh_terms: D000071181:ATP Binding Cassette Transporter, Subfamily B, Member 2; D018528:ATP-Binding Cassette Transporters / Q000235:genetics* / Q000378:metabolism; D000483:Alleles; D001483:Base Sequence; D044383:Black People / Q000235:genetics*; D005006:Ethnicity / Q000235:genetics; D005787:Gene Frequency; D005805:Genes, MHC Class I; D020022:Genetic Predisposition to Disease; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D016133:Polymerase Chain Reaction; D018807:Polymorphism, Single-Stranded Conformational; D015030:Zimbabwe
chemical_list: D000071181:ATP Binding Cassette Transporter, Subfamily B, Member 2; D018528:ATP-Binding Cassette Transporters; C073119:TAP1 protein, human