Expression and Functional Analyses of EXO70 Genes in Arabidopsis Implicate Their Roles in Regulating Cell Type-Specific Exocytosis
Expression and Functional Analyses of EXO70 Genes in Arabidopsis Implicate Their Roles in Regulating Cell Type-Specific Exocytosis
复制标题
拟南芥中 EXO70 基因的表达和功能分析表明它们在调节细胞类型特异性胞吐作用中的作用
DOI：
10.1104/pp.110.164178
复制
发表时间：
2010-12-01
期刊：
影响因子：
7.4
通讯作者：
Liu, Chun-Ming
中科院分区：
文献类型：
--
作者：
Li, Shipeng;van Os, Gwen M. A.;Liu, Chun-Ming
在胞吐过程中，高尔基体衍生的囊泡被一种被称为胞囊的保守的八聚体复合体拴在目标质膜上。与酵母和大多数动物中的单一基因相比，植物基因组中的Exo70基因数量大大增加，其功能非常未知。利用逆转录-聚合酶链式反应技术对拟南芥中所有23个外显子70基因进行检测，以检测其在器官水平上的表达。利用携带β-葡萄糖醛酸酶报告基因的转基因植物进行了细胞水平的表达分析，结果表明Exo70基因主要在潜在的胞吐活性细胞中表达，如顶端生长和伸长的细胞、发育中的木质部元素和保卫细胞，而在成熟器官的细胞中没有表达，如发育良好的叶、茎、萼片和花瓣。在小孢子发育和花粉萌发过程中，6个Exo70基因在不同但部分重叠的阶段表达。其中一个基因EXO70C1(At5g13150)的突变导致花粉管生长迟缓，并危及男性传播。这项研究表明，Exo70基因的倍增可能允许植物获得细胞类型和/或货物特异性的胞吐调节机制。
During exocytosis, Golgi-derived vesicles are tethered to the target plasma membrane by a conserved octameric complex called the exocyst. In contrast to a single gene in yeast and most animals, plants have greatly increased number of EXO70 genes in their genomes, with functions very much unknown. Reverse transcription-polymerase chain reactions were performed on all 23 EXO70 genes in Arabidopsis (Arabidopsis thaliana) to examine their expression at the organ level. Cell-level expression analyses were performed using transgenic plants carrying beta-glucuronidase reporter constructs, showing that EXO70 genes are primarily expressed in potential exocytosis-active cells such as tip-growing and elongating cells, developing xylem elements, and guard cells, whereas no expression was observed in cells of mature organs such as well-developed leaves, stems, sepals, and petals. Six EXO70 genes are expressed in distinct but partially overlapping stages during microspore development and pollen germination. A mutation in one of these genes, EXO70C1 (At5g13150), led to retarded pollen tube growth and compromised male transmission. This study implies that multiplications of EXO70 genes may allow plants to acquire cell type-and/or cargo-specific regulatory machinery for exocytosis.