title: Alpha S1-casein polymorphisms in camel (Camelus dromedarius) and descriptions of biological active peptides and allergenic epitopes.
abstract: Milk samples of 193 camels (Camelus dromedarius) from different regions of Sudan were screened for casein variability by isoelectric focusing. Kappa-casein and beta-casein were monomorphic, whereas three protein patterns named αs1-casein A, C, and D were identified. The major allele A revealed frequencies of 0.79 (Lahaoi), 0.75 (Shanbali), 0.90 (Arabi Khali), and 0.88 (Arabi Gharbawi) in the different ecotypes. CSN1S1*C shows a single G > T nucleotide substitution in the exon 5, leading to a non-synonymous amino acid exchange (p.Glu30 > Asp30) in comparison to CSN1S1*A and D. At cDNA level, no further single nucleotide polymorphisms could be identified in CSN1S1* A, C, and D, whereas the variants CSN1S1*A and CSN1S1*C are characterized by missing of exon 18 compared to the already described CSN1S1*B, as consequence of DNA insertion of 11 bp at intron 17 which alter the pre-mRNA spliceosome machinery. A polymerase chain-restriction fragment length polymorphism method (PCR-RFLP) was established to type for G > T nucleotide substitution at genomic DNA level. The occurrence and differences of IgE-binding epitopes and bioactive peptides between αs1-casein A, C, and D after digestion were analyzed in silico. The amino acid substitutions and deletion affected the arising peptide pattern and thus modifications between IgE-binding epitopes and bioactive peptides of the variants were found. The allergenic potential of these different peptides will be investigated by microarray immunoassay using sera from milk-sensitized individuals, as it was already demonstrated for bovine αs1-casein variants.
authors.affiliation: Department of Animal Breeding and Genetics, Justus-Liebig-University Giessen, Ludwigstr. 21B, 35390, Giessen, Germany. georg.erhardt@agrar.uni-giessen.de.
authors.forename: Georg
authors.initials: G
authors.lastname: Erhardt
authors.affiliation: Department of Animal Breeding and Genetics, Justus-Liebig-University Giessen, Ludwigstr. 21B, 35390, Giessen, Germany.|Institute of Molecular Biology, University of Nyala, 155, Nyala, Sudan.
authors.forename: El Tahir Salih
authors.initials: el TS
authors.lastname: Shuiep
authors.affiliation: Department of Animal Breeding and Genetics, Justus-Liebig-University Giessen, Ludwigstr. 21B, 35390, Giessen, Germany.
authors.forename: Maria
authors.initials: M
authors.lastname: Lisson
authors.affiliation: Department of Animal Breeding and Genetics, Justus-Liebig-University Giessen, Ludwigstr. 21B, 35390, Giessen, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Weimann
authors.affiliation: Department of Animal Breeding and Genetics, Justus-Liebig-University Giessen, Ludwigstr. 21B, 35390, Giessen, Germany.
authors.forename: Zhaoxin
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Department of Dairy Production, University of Khartoum, P.O. Box 321, Khartoum, Sudan.
authors.forename: Ibtisam El Yas Mohamed
authors.initials: Iel Y
authors.lastname: El Zubeir
authors.affiliation: Department of Animal Breeding and Genetics, Justus-Liebig-University Giessen, Ludwigstr. 21B, 35390, Giessen, Germany.|Department of Agricultural, Forest and Food Sciences (DISAFA), University of Torino, Largo Paolo Braccini, 2, 10095, Grugliasco (TO), Italy.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Pauciullo
mesh_terms: D000483:Alleles; D000485:Allergens / Q000737:chemistry* / Q000235:genetics; D019943:Amino Acid Substitution; D000818:Animals; D002162:Camelus / Q000502:physiology*; D002364:Caseins / Q000737:chemistry* / Q000378:metabolism; D000939:Epitopes / Q000235:genetics*; D007118:Immunoassay; D008892:Milk / Q000737:chemistry*; D010455:Peptides; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D012150:Polymorphism, Restriction Fragment Length; D013397:Sudan
chemical_list: D000485:Allergens; D002364:Caseins; D000939:Epitopes; D010455:Peptides
keywords: Bioactive peptides; CSN1S1; Genetic polymorphisms; IgE-binding epitopes; Milk proteins