title: Purification, identification, and cDNA cloning of Jun a 2, the second major allergen of mountain cedar pollen.
abstract: The second major allergen of Juniperus ashei (mountain cedar) pollen, Jun a 2, has been purified and its cDNA cloned. The purified protein has a molecular mass of 43 kDa and its N-terminal 9-residue amino acid sequence is highly homologous to those of Cry j 2 and Cha o 2, the second major allergen of Cryptomeria japonica and Chamaecyparis obtusa pollen, respectively. cDNA clones encoding Jun a 2 were isolated after PCR based amplification, and their nucleotide sequences were determined. The cDNA contains an open reading frame of 507 amino acid residues, and encodes a putative 54-residue signal sequence and a 453-residue intermediate, which releases a C-terminal fragment upon maturation. Three possible N-linked glycosylation sites and 20 cystein-residues are found in the deduced amino acid sequence. The amino acid sequence of Jun a 2 shows 70.7 and 82.0% identity with those of Cry j 2 and Cha o 2, respectively. Immunological observations that IgE antibodies in sera of Japanese pollinosis patients bind not only to Cry j 2 and Cha o 2 but also to Jun a 2 strongly suggest that Jun a 2 is an allergen of mountain cedar pollen, and that allergenic epitopes of these three allergens are similar.
authors.affiliation: Meiji Milk Products Company, Ltd., 540 Naruda, Odawara, Kanagawa, 250-0862, Japan. MINEHIKO_YOKOYAMA@MEIJI-MILK.COM
authors.forename: M
authors.initials: M
authors.lastname: Yokoyama
authors.forename: M
authors.initials: M
authors.lastname: Miyahara
authors.forename: K
authors.initials: K
authors.lastname: Shimizu
authors.forename: K
authors.initials: K
authors.lastname: Kino
authors.forename: H
authors.initials: H
authors.lastname: Tsunoo
mesh_terms: D000485:Allergens / Q000737:chemistry / Q000235:genetics* / Q000276:immunology* / Q000302:isolation & purification; D000595:Amino Acid Sequence; D052179:Antigens, Plant; D001483:Base Sequence; D015153:Blotting, Western; D003001:Cloning, Molecular; D000939:Epitopes / Q000276:immunology; D006031:Glycosylation; D006801:Humans; D006967:Hypersensitivity / Q000097:blood / Q000276:immunology; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics* / Q000276:immunology* / Q000302:isolation & purification; D011058:Pollen / Q000737:chemistry* / Q000276:immunology*; D011994:Recombinant Proteins / Q000276:immunology; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014197:Trees / Q000235:genetics / Q000276:immunology*
chemical_list: D000485:Allergens; D052179:Antigens, Plant; C065291:Cry j II protein, Cryptomeria japonica; D000939:Epitopes; C413365:Jun a 2 protein, Juniperus ashei; D010940:Plant Proteins; D011994:Recombinant Proteins; D007073:Immunoglobulin E