title: Group I allergens of grass pollen as cell wall-loosening agents.
abstract: Group I allergens are the major allergens of grass pollen, but their biological function is unknown. These proteins are shown here to be structurally related to expansins, which are able to induce extension (creep) of plant cell walls. Extracts of maize pollen possess potent expansin-like activity, as measured in wall extension and wall stress-relaxation assays. This activity is selective for grass cell walls and is, at least partly, due to the action of maize group I allergens. We propose that group I allergens facilitate invasion of the pollen tube into the maternal tissues by loosening the cell walls of the grass stigma and style. Additionally, the presence of related mRNAs in vegetative tissues of rice, Arabidopsis, and soybean implies that allergen homologs may function to loosen walls in growing vegetative tissues as well.
authors.affiliation: Department of Biology, 208 Mueller Laboratory, Pennsylvania State University, University Park, PA 16802, USA. dcosgrove@psu.edu
authors.forename: D J
authors.initials: DJ
authors.lastname: Cosgrove
authors.forename: P
authors.initials: P
authors.lastname: Bedinger
authors.forename: D M
authors.initials: DM
authors.lastname: Durachko
mesh_terms: D000485:Allergens / Q000737:chemistry* / Q000502:physiology; D000595:Amino Acid Sequence; D002473:Cell Wall / Q000502:physiology; D017124:Conserved Sequence; D008961:Models, Structural; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry*; D006109:Poaceae / Q000235:genetics / Q000276:immunology / Q000502:physiology*; D011058:Pollen / Q000276:immunology / Q000502:physiology*; D017433:Protein Structure, Secondary; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D003313:Zea mays / Q000276:immunology / Q000502:physiology
chemical_list: D000485:Allergens; D010940:Plant Proteins; C095825:expansin protein, plant