Distribution of Callose Synthase, Cellulose Synthase, and Sucrose Synthase in Tobacco Pollen Tube Is Controlled in Dissimilar Ways by Actin Filaments and Microtubules
Distribution of Callose Synthase, Cellulose Synthase, and Sucrose Synthase in Tobacco Pollen Tube Is Controlled in Dissimilar Ways by Actin Filaments and Microtubules
复制标题
DOI：
10.1104/pp.110.171371
复制
发表时间：
2011-03-01
期刊：
影响因子：
7.4
通讯作者：
Cresti, Mauro
中科院分区：
文献类型：
--
作者：
Cai, Giampiero;Faleri, Claudia;Cresti, Mauro
胼胝质和纤维素是花粉管细胞壁的基本成分，可能分别由胼胝质合成酶和纤维素合成酶合成。我们研究了烟草（Nicotiana tabacum）花粉管中胼胝质合成酶和纤维素合成酶的分布与肌动蛋白丝，微管和内膜系统的动态关系，使用特异性抗体高度保守的肽序列。使用特异性抑制剂（latrunculin B、2，3-丁二酮单肟、紫杉醇、安磺灵和布雷菲德菌素A）研究了细胞骨架和膜流动的作用。这两种酶都与质膜有关，但纤维素合成酶沿着整个花粉管长度存在（在顶端浓度较高），而胼胝质合成酶位于顶端和远端区域。在较长的花粉管中，胼胝质合成酶在胼胝质塞周围持续积累，表明它参与了塞的合成。肌动蛋白丝和内膜动力学的胼胝质合成酶和纤维素合成酶的分布是至关重要的，表明酶是通过高尔基体和/或囊泡移动沿着肌动蛋白丝。相反，微管似乎是至关重要的定位胼胝质合成酶在远端区域和周围的胼胝质塞。与此相反，纤维素酶仅部分与皮质微管对齐，与胼胝质塞无关。通过Blue Native聚丙烯酰胺凝胶电泳，胼胝质合成酶也与微管蛋白共迁移。膜蔗糖合成酶，它提供UDP-葡萄糖胼胝质合成酶和纤维素合成酶，结合肌动蛋白丝依赖于蔗糖浓度;其分布依赖于肌动蛋白细胞骨架和内膜系统，但不依赖于微管。
Callose and cellulose are fundamental components of the cell wall of pollen tubes and are probably synthesized by distinct enzymes, callose synthase and cellulose synthase, respectively. We examined the distribution of callose synthase and cellulose synthase in tobacco (Nicotiana tabacum) pollen tubes in relation to the dynamics of actin filaments, microtubules, and the endomembrane system using specific antibodies to highly conserved peptide sequences. The role of the cytoskeleton and membrane flow was investigated using specific inhibitors (latrunculin B, 2,3-butanedione monoxime, taxol, oryzalin, and brefeldin A). Both enzymes are associated with the plasma membrane, but cellulose synthase is present along the entire length of pollen tubes (with a higher concentration at the apex) while callose synthase is located in the apex and in distal regions. In longer pollen tubes, callose synthase accumulates consistently around callose plugs, indicating its involvement in plug synthesis. Actin filaments and endomembrane dynamics are critical for the distribution of callose synthase and cellulose synthase, showing that enzymes are transported through Golgi bodies and/or vesicles moving along actin filaments. Conversely, microtubules appear to be critical in the positioning of callose synthase in distal regions and around callose plugs. In contrast, cellulose synthases are only partially coaligned with cortical microtubules and unrelated to callose plugs. Callose synthase also comigrates with tubulin by Blue Native-polyacrylamide gel electrophoresis. Membrane sucrose synthase, which expectedly provides UDP-glucose to callose synthase and cellulose synthase, binds to actin filaments depending on sucrose concentration; its distribution is dependent on the actin cytoskeleton and the endomembrane system but not on microtubules.