1. An extracellular transglutaminase is required for apple pollen tube growth
- Author
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Alan J. Hargreaves, Stefano Del Duca, Alessandra Scarpellini, Mauro Cresti, Elisabetta A.M. Verderio, Alessia Di Sandro, Giampiero Cai, Donatella Serafini-Fracassini, Yutaka Furutani, Shigehisa Hirose, Philip L.R. Bonner, Ian G. C. Coutts, Rosa Anna Iorio, Martin Griffin, Claudia Faleri, Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO), Di Sandro A, Del Duca S, Verderio EA, Hargreaves AJ, Scarpellini A, Cai G, Cresti M, Faleri C, Iorio RA, Hirose S, Furutani Y, Coutts IG, Griffin M, Bonner PL, and Serafini D
- Subjects
0106 biological sciences ,Malus ,Tissue transglutaminase ,Green Fluorescent Proteins ,Germination ,Pollen Tube ,Biology ,medicine.disease_cause ,Models, Biological ,01 natural sciences ,Biochemistry ,Substrate Specificity ,Green fluorescent protein ,Cell wall ,03 medical and health sciences ,Pollen ,otorhinolaryngologic diseases ,medicine ,Extracellular ,Molecular Biology ,030304 developmental biology ,0303 health sciences ,Transglutaminases ,POLLEN TUBER GROWTH ,integumentary system ,Life Sciences ,food and beverages ,Extracellular localization Malus domestica Pollen tube growth Polyamine Protein cross-link Transglutaminase ,Cell Biology ,Plants, Genetically Modified ,biology.organism_classification ,Immunohistochemistry ,Recombinant Proteins ,POLYAMINES ,PROTEIN CROSS-LINK ,TRANSGLUTAMINASE ,biology.protein ,Pollen tube ,Extracellular Space ,010606 plant biology & botany - Abstract
International audience; An extracellular form of the Ca2+-dependent protein-cross-linking enzyme transglutaminase (TGase) was demonstrated to be involved in the apical growth of Malus domestica pollen tube. Apple pollen transglutaminase and its substrates were co-localized within aggregates on the pollen tube surface, as determined by indirect immuno-fluorescence staining and the in situ cross-linking of fluorescently labeled substrates. Transglutaminase-specific inhibitors and an anti-TGase monoclonal antibody blocked pollen tube growth, whereas incorporation of a recombinant fluorescent mammalian TGase substrate (histidine-tagged green fluorescent protein: His6-Xpr-GFP) into the growing tube wall enhanced tube length and germination, consistent with a role of TGase as modulator of cell wall building and strengthening. The secreted pollen TGase catalyzed the cross-linking of both polyamines (PAs) into proteins (released by the pollen tube) and His6-Xpr-GFP into endogenous or exogenously added substrates. A similar distribution of TGase activity was observed in planta on pollen tubes germinating inside the style, consistent with a possible additional role for TGase in the interaction between the pollen tube and the style during fertilization.
- Published
- 2010