NUCLEOTIDE-SEQUENCE OF CDNA-ENCODING THE GROUP-II ALLERGEN OF COCKSFOOT ORCHARD GRASS (DACTYLIS-GLOMERATA), DAC G-II

Cocksfoot/orchard grass (Dactylis glomerata) anther cDNA clones encodi ng the group II allergen Dac g II were previously isolated on the basi s of immunoreactivity of human, rabbit, and murine antibodies with a 2 4-kDa protein expressed as a fusion protein with beta-galactosidase. N ucleotide sequencing reveals an open reading frame predicting expressi on of a 98-amino-acid (11-kDa) polypeptide exhibiting > 90 % homology with the group II allergen of Lolium perenne, Lol p II. In vitro trans lation of different sized clone fragments generated by polymerase chai n amplification confirms eukaryotic expression of a 10-12-kDa polypept ide by SDS-PAGE and the position of a translational stop apparently un recognized during expression of lambdagt11 in E. coli. The unusual cha racteristics of the prokaryote-expressed fusion proteins may be exerti ng conformational alterations in Dac g II, as reflected by previous de monstrations of differences in human IgE immunoreactivity. Northern bl ot analysis using PCR-generated partial and full-length probes suggest s that group Il allergens may be encoded by a different family or fami lies of temporally expressed genes from those encoding group I major a llergens, although a group I gene may have been the progenitor.