A model system to study the environment-dependent expression of the Bet v 1a gene encoding the major birch pollen allergen.
BACKGROUND
The major birch pollen allergen Bet v 1 (or Bet v 1a) is one of the main causes of seasonal type I allergies. Various environmental factors such as light, temperature and air pollution may influence the activity of the Bet v 1a gene. The creation of a model system to evaluate the role of environmental factors affecting the Bet v 1a gene expression would be highly desirable. We suggest the use of transgenic tobacco plants carrying a Bet v 1a promoter-reporter gene fusion as such a system.


METHODS
The promoter of the Bet v 1a gene was isolated with the use of the Universal Genome Walker kit (BD Biosciences Clontech, USA). Web Software was used to search for putative cis-regulatory elements within the promoter. Transgenic tobacco plants harboring the promoter-beta-glucuronidase (GUS) reporter gene fusion were obtained via Agrobacterium tumefaciens-mediated transformation. Promoter activity was examined with histochemical and quantitative assays.


RESULTS
Structural analysis predicted elements responsible for pollen-specific, light-, stress- and hormone-mediated induction within the Bet v 1a promoter. The evaluation of GUS activity in transgenic tobacco plants showed that the Bet v 1a promoter is pollen-specific. Moreover, the Bet v 1a promoter is considered to be the strongest isolated pollen-specific promoter reported to date. It was shown that temperature and abscisic acid positively regulate the activity of the Bet v 1a promoter during pollen development, providing evidence for environment-dependent regulation of the Bet v 1a gene.


CONCLUSIONS
A model system to study the effect of environmental factors on the expression of the Bet v 1a gene encoding the major birch allergen in pollen was generated. Additionally, we suggest that this system could be used to search for factors that inhibit the activity of the gene in pollen in order to reduce the potential allergenicity of birch trees.
Tashpulatov
Alisher S
AS
Vienna Biocenter, Institute of Microbiology and Genetics, Vienna University, Vienna, Austria. alisher.touraev@univie.ac.at
Clement
Patrick
P
Akimcheva
Svetlana A
SA
Belogradova
Kristina A
KA
Barinova
Ioulia
I
Rakhmawaty
Fadilla D
FD
Heberle-Bors
Erwin
E
Touraev
Alisher
A
D000040:Abscisic Acid / Q000494:pharmacology; D000393:Air Pollutants / Q000276:immunology*; D000485:Allergens / Q000096:biosynthesis* / Q000235:genetics* / Q000302:isolation & purification; D052179:Antigens, Plant; D001483:Base Sequence; D029662:Betula / Q000235:genetics* / Q000276:immunology*; D018076:DNA, Complementary / Q000235:genetics; D005470:Fluorometry; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000235:genetics; D017343:Genes, Plant / Q000187:drug effects / Q000235:genetics; D005815:Genetic Code / Q000235:genetics*; D005966:Glucuronidase / Q000187:drug effects / Q000235:genetics; D006801:Humans; D008969:Molecular Sequence Data; D010937:Plant Growth Regulators / Q000494:pharmacology; D010940:Plant Proteins / Q000096:biosynthesis* / Q000235:genetics* / Q000302:isolation & purification; D011058:Pollen / Q000235:genetics* / Q000276:immunology; D011401:Promoter Regions, Genetic / Q000235:genetics; D014176:Protein Biosynthesis / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000187:drug effects / Q000235:genetics; D013696:Temperature; D014158:Transcription, Genetic / Q000235:genetics
D000393:Air Pollutants; D000485:Allergens; D052179:Antigens, Plant; D018076:DNA, Complementary; D010937:Plant Growth Regulators; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; C061312:Bet v 1 allergen, Betula; D000040:Abscisic Acid; D005966:Glucuronidase