Characterization of in vivo functions of Nicotiana benthamiana RabE1
Characterization of in vivo functions of Nicotiana benthamiana RabE1
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DOI：
10.1007/s00425-012-1760-5
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发表时间：
2013-01-01
期刊：
影响因子：
4.3
通讯作者：
Pai, Hyun-Sook
中科院分区：
文献类型：
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作者：
Ahn, Chang Sook;Han, Jeong-A;Pai, Hyun-Sook
我们研究了属于Rabe家族的烟草小GTP酶的基因表达、亚细胞定位和体内功能，命名为NbRabE1。NbRabE1启动子在含有活跃分裂细胞的年轻组织和气孔保卫细胞中驱动β-葡萄糖醛酸酶报告基因的表达。NbRabE1的GFP融合蛋白及其显性-阴性突变体和成分活性突变体都定位于高尔基体和质膜，但对膜的附着表现出不同的亲和力。病毒诱导的NbRabE1基因沉默导致多效性表型，包括生长停滞、早衰和叶片发育异常。在细胞水平上，沉默NbRabE1的叶片含有异常气孔，气孔缺乏气孔或腹壁不完整，表明NbRabE1缺失导致保卫细胞胞质分裂缺陷。NbRabE1的显性-负性突变体在拟南芥中的异位表达导致了地上部和根的生长迟缓，并伴随着根毛的形成缺陷。这些发育缺陷与Rabe GTP酶在极化分泌囊泡运输中的拟议功能一起被讨论。
We characterized the gene expression, subcellular localization, and in vivo functions of a Nicotiana benthamiana small GTPase belonging to the RabE family, designated NbRabE1. The NbRabE1 promoter drove strong beta-glucuronidase reporter expression in young tissues containing actively dividing cells and in stomata guard cells. GFP fusion proteins of NbRabE1 and its dominant-negative and constitutively active mutants were all localized to the Golgi apparatus and the plasma membrane but showed different affinities for membrane attachment. Virus-induced gene silencing of NbRabE1 resulted in pleiotropic phenotypes, including growth arrest, premature senescence, and abnormal leaf development. At the cellular level, the leaves in which NbRabE1 was silenced contained abnormal stomata that lacked pores or contained incomplete ventral walls, suggesting that NbRabE1 deficiency leads to defective guard cell cytokinesis. Ectopic expression of the dominant-negative mutant of NbRabE1 in Arabidopsis thaliana resulted in retardation of shoot and root growth accompanied by defective root hair formation. These developmental defects are discussed in conjunction with proposed functions of RabE GTPases in polarized secretory vesicle trafficking.