Characterization of genes for a pollen allergen, Cry j 2, of Cryptomeria japonica.
BACKGROUND
Cry j 2 is one of the major pollen allergens of Cryptomeria japonica. The polymorphism of Cry j 2 isoforms and the conservation of the structure of Cry j 2 in coniferous species remain to be analyzed.


METHODS
A cDNA library derived from the pollen of C. japonica was screened using a fragment of Cry j 2 cDNA. Restriction fragment length polymorphism analysis was performed to examine the diversity of Cry j 2 genes. The promoters of Cry j 2 genes were isolated with a commercially available cloning kit. Clonal variations in the expression of Cry j 2 in pollen were examined by RNA gel blot analysis, and the conservation of the structure of the Cry j 2 gene in coniferous species was evaluated by DNA gel blot analysis.


RESULTS
We isolated three cDNA clones encoding novel isoforms of Cry j 2. We also sequenced a total of 16 promoter regions from 10 specimens. The sequences of promoter regions of Cry j 2 genes were highly divergent. The amount of Cry j 2 mRNA also varied considerably. The Cry j 2 gene was found to be conserved among species belonging to Taxodiaceae and Cupressaceae but to vary between Taxodiaceae and Pinaceae.


CONCLUSIONS
The coding and promoter regions of Cry j 2 genes contain large numbers of polymorphisms. Our analysis revealed large variations in the expression of Cry j 2 at the transcriptional level, and we suggest that conserved homologs of Cry j 2 confer cross-allergenicity among Taxodiaceae and Cupressaceae.
Futamura
N
N
Department of Molecular and Cell Biology, Forestry and Forest Products Research Institute, Ibaraki, Japan. futa@ffpri.affrc.go.jp
Kusunoki
Y
Y
Mukai
Y
Y
Shinohara
K
K
D000485:Allergens / Q000276:immunology*; D000595:Amino Acid Sequence; D001483:Base Sequence; D032485:Cryptomeria / Q000276:immunology*; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics*; D011058:Pollen / Q000276:immunology*; D011110:Polymorphism, Genetic; D011401:Promoter Regions, Genetic; D014158:Transcription, Genetic
D000485:Allergens; C065291:Cry j II protein, Cryptomeria japonica; D010940:Plant Proteins