Molecular characterization of the IgE-binding epitopes in the fast ω-gliadins of Triticeae in relation to wheat-dependent, exercise-induced anaphylaxis

• Published in: Gene 2016-10, Vol.591 (1), p.27-33
• Main Authors: Du, Xuye, Tang, Heng, Li, Min, Ma, Xin, Yin, Huayan, Wang, Hongwei, Zhang, Xiaocun, Qiao, Xuguang, Li, Anfei, Kong, Lingrang
• Format: Article
• Language: English
• Subjects: Allergy; Amino Acid Sequence; Anaphylaxis - etiology; Anaphylaxis - immunology; Cloning, Molecular; Epitopes - genetics; Exercise; Fast ω-gliadin; Genes, Plant; Gliadin - chemistry; Gliadin - genetics; Humans; Hypersensitivity - immunology; IgE-binding epitopes; Immunoglobulin E - genetics; Phylogeny; Polymerase Chain Reaction; Triticeae; Triticum - genetics; Triticum aestivum; Variation
• ISSN: 0378-1119; 1879-0038
• DOI: 10.1016/j.gene.2016.06.040

Fast ω-gliadins were minor components of wheat storage proteins but a major antigen triggering allergy to wheat. Sixty-six novel full-length fast ω-gliadin genes with unique characteristics were cloned and sequenced from wheat and its relative species using a PCR-based strategy. Their coding regions ranged from 177bp to 987bp in length and encoded 4.28kDa to 37.56kDa proteins. On the base of first three deduced amino acids at the N-terminal, these genes could be classified into the six subclasses of SRL-, TRQ-, GRL-, NRL-, SRP- and SRM-type ω-gliadin genes. Compared by multiple alignments, these genes were significantly different from each other, due to the insertion or deletion at the repetitive domain. An analysis of the IgE-binding epitopes of the 66 deduced fast ω-gliadins demonstrated that they contained 0–24 IgE-binding epitopes. The phylogenetic tree demonstrated that the fast ω-gliadins and slow ω-gliadins were separated into two groups and their divergence time was 21.64millionyears ago. Sequence data of the fast ω-gliadin genes assist in the study of the origins and evolutions of the different types of ω-gliadins while also providing a basis for the synthesis of monoclonal antibodies to detect wheat antigen content. •We cloned 66 novel fast ω-gliadin genes from Triticeae.•The genes could be classified into the six subclasses according to the N-terminal domain.•The deduced fast ω-gliadins contained IgE-binding epitopes.•Fast ω-gliadins and ω1,2-gliadins were separated into two groups in evolutionary analysis.