An extracellular transglutaminase is required for apple pollen tube growth
An extracellular transglutaminase is required for apple pollen tube growth
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DOI：
10.1042/bj20100291
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发表时间：
2010-07-15
影响因子：
4.1
通讯作者：
Serafini-Fracassini, Donatella
中科院分区：
文献类型：
--
作者：
Di Sandro, Alessia;Del Duca, Stefano;Serafini-Fracassini, Donatella
一种胞外形式的钙依赖蛋白交联酶TGase(转谷氨酰胺酶)被证明参与了家蝇花粉管的顶端生长。通过间接免疫荧光染色和荧光标记底物的原位交联法确定，苹果花粉TGase及其底物共定位于花粉管表面的聚集体中。TGase特异性抑制剂和抗TGase单抗抑制了花粉管的生长，而重组荧光哺乳动物TGase底物(组氨酸标记的绿色荧光蛋白：His(6)-Xpr-GFP)进入生长管壁增加了管的长度和萌发，这与TGase作为细胞壁建立和加强的调节器的作用一致。分泌的花粉TGase催化Pas(多胺)形成蛋白质(由花粉管释放)和His(6)-Xpr-GFP形成内源或外源添加底物。在花柱内萌发的花粉管平台上也观察到类似的TGase活性分布，这可能与TGase在受精过程中花粉管与花柱之间的相互作用中所起的额外作用相一致。
An extracellular form of the calcium-dependent protein-cross-linking enzyme TGase (transglutaminase) was demonstrated to be involved in the apical growth of Mains domestica pollen tube. Apple pollen TGase and its substrates were co-localized within aggregates on the pollen tube surface, as determined by indirect immunofluorescence staining and the in situ cross-linking of fluorescently labelled substrates. TGase-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: His(6)-Xpr-GFP) into the growing tube wall enhanced tube length and germination, consistent with a role of TGase as a modulator of cell wall building and strengthening. The secreted pollen TGase catalysed the cross-linking of both PAs (polyamines) into proteins (released by the pollen tube) and His(6)-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.