T. Midoro-horiuti et al., Molecular cloning of the mountain cedar (Juniperus ashei) pollen major allergen, Jun a 1, J ALLERG CL, 104(3), 1999, pp. 613-617
Background: Cedar pollens cause allergic disease in diverse geographic area
s. We have recently purified and characterized the major mountain cedar (Ju
niperus ashei) pollen allergen, Jun a 1.
Objective: A full-length complementary DNA for Jun a 1 was cloned and seque
nced, and the recombinant protein was expressed,
Methods: Messenger RNA from mountain cedar pollen was purified and Jun a 1
sequences were established with use of reverse transcriptase-PCR and primer
s based on the N-terminal amino acid sequence of Jun a 1 and the homologous
protein Cry j 1. Portions of the nucleotide sequence were confirmed by com
parison with N-terminal amino acid sequencing of the intact tryptic fragmen
ts of the purified native protein. Recombinant Jun a 1 was cloned into pET
30, expressed in BL21, and purified by HPLC, and its allergenicity mas anal
yzed by Western blotting with patient sera.
Results: Jun a 1 possesses a high level of amino acid sequence homology wit
h Cha o 1 and Cry j 1, the major allergens of Japanese cypress and Japanese
cedar. The amino acid sequence of a region with putative pectate lyase act
ivity mas identical to that of Cry j 1 and Cha o 1. Jun a 1 contained 2 pot
ential N-glycosylation sites that mere distinct from those found in Cry j 1
, The IgE from patient sera bound recombinant Jun a 1 in Western blot analy
sis.
Conclusion: The high degree of homology of Jun a 1 with Cha o 1 and Cry j 1
may explain the cross-reactivity of conifer pollens. Differences in N-glyc
osylation suggest little overlap of glycopeptide epitopes.