Cloning and sequencing of cDNA coding for Cry j I, a major allergen of Japanese cedar pollen.

cDNA clones coding for Cry j I, a major allergen of the Japanese cedar (Cryptomeria japonica) pollen, have been isolated. Two of the clones were sequenced and found to code for a putative 21-residue signal peptide and a 353-residue mature protein with a derived molecular weight of 38.5 KDa. Five possible N-linked glycosylation sites were found in the sequence. Comparison of the nucleotide sequences of the two clones revealed sixteen nucleotide differences and these led to five amino acid exchanges in the mature allergen, indicating that an isoform of the Cry j I molecule exists. The deduced amino acid sequence of the Cry j I shows 46-48% identities with those of the Amb a I family and Amb a II, the major allergens of short ragweed. These findings should facilitate study of the structure-function relationship between the allergen and the immunocompetent cells.