title: Characterization of in vivo functions of Nicotiana benthamiana RabE1.
abstract: 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 β-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.
authors.affiliation: Department of Systems Biology, Yonsei University, Seoul 120-749, Korea.
authors.forename: Chang Sook
authors.initials: CS
authors.lastname: Ahn
authors.forename: Jeong-A
authors.initials: JA
authors.lastname: Han
authors.forename: Hyun-Sook
authors.initials: HS
authors.lastname: Pai
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D015153:Blotting, Western; D002462:Cell Membrane / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D020868:Gene Silencing; D005966:Glucuronidase / Q000235:genetics / Q000378:metabolism; D006056:Golgi Apparatus / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission; D008969:Molecular Sequence Data; D009154:Mutation; D010802:Phylogeny; D018515:Plant Leaves / Q000235:genetics / Q000254:growth & development; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D054046:Plant Stomata / Q000235:genetics / Q000254:growth & development / Q000648:ultrastructure; D010942:Plant Viruses / Q000235:genetics; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014026:Nicotiana / Q000235:genetics* / Q000254:growth & development / Q000821:virology; D020691:rab GTP-Binding Proteins / Q000145:classification / Q000235:genetics* / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D049452:Green Fluorescent Proteins; D005966:Glucuronidase; D020691:rab GTP-Binding Proteins