Two novel Jk(null) alleles derived from 222CA in Exon 5 and 896GA in Exon 9 of the JK gene

Autor: Hsueng-Mei, Liu, Jeong-Shi, Lin, Pei-Shan, Chen, Jau-Yi, Lyou, Ying-Ju, Chen, Cheng-Hwai, Tzeng
Rok vydání: 2008
Předmět:
Zdroj: Transfusion. 49(2)
ISSN: 1537-2995
Popis: Polynesian Jk(null) is well known for its mutation as Intron 5 ga at the 3' splice acceptor site. After sequencing analysis, however, it was noticed that only three of eight samples with the Jknull phenotype carried typical homozygous Polynesian Jk(null) mutation. Five others were noted to be unreported heterozygous Polynesian Jk(null) mutation. An investigation was then conducted to characterize the underlying mechanism leading to this particular Jk(null) genotype.Genomic DNA covering 5'-untranslated region exons and intervening introns of the JK gene was amplified by polymerase chain reaction, and the fragments were directly sequenced. The sequencing results were compared with those published in literature and related biologic Web sites.In all five samples with a heterozygous Polynesian Jk(null) mutation, additional mutations were identified. Two samples carried missense mutations: 222CA (Asn74Lys) in Exon 5 and 499AG (Met167Val) in Exon 7. Three others had missense mutation 896GA (Gly299Glu) in Exon 9. These substituted amino acids were located either near or at transmembrane domains, respectively. In addition, two polymorphic nucleotides at positions -103 (ag) and -119(ca) from the 3' end of Intron 1 were also Polynesian mutation-related.In contrast to the typical homozygous Polynesian Jk(null) mutation, two novel heterozygous Jk(null) alleles were noted to be associated with the Jknull phenotype. One carried missense mutation 222CA in Exon 5, and the other had 896GA missense mutation in Exon 9. These findings may have implications in designing a molecular screening assay for people with the Jknull phenotype.
Databáze: OpenAIRE