Sato M H, Nakamura N, Ohsumi Y, Kouchi H, Kondo M, Hara-Nishimura I, Nishimura M, Wada Y
Department of Biology, Graduate School of Arts and Sciences, University of Tokyo, Komaba, Tokyo 153, Japan.
J Biol Chem. 1997 Sep 26;272(39):24530-5. doi: 10.1074/jbc.272.39.24530.
The vacuole constitutes a large compartment in plant and fungal cells. The VAM3 gene of Saccharomyces cerevisiae encodes a syntaxin-related protein required for vacuolar assembly. An Arabidopsis thaliana cDNA library, designed for expression in S. cerevisiae, was screened for cDNAs able to complement defective vacuolar assembly of the Deltavam3 mutation. One cDNA, encoding a 33-kDa protein with structural similarities to the other syntaxins, was identified. The product of AtVAM3 (AtVam3p) was expressed in various tissues including roots, leaves, inflorescence stems, flower buds, and young siliques. The AtVAM3 transcripts were abundant in undifferentiated cells in the meristematic region. AtVam3p fractionated predominantly to an 8,000 x g pellet fraction where a vacuolar membrane protein H+-translocating inorganic pyrophosphatase (H+-PPase) also fractionated. Immunoelectron microscopy showed that AtVam3p was localized to restricted regions on the vacuolar membranes. We propose that AtVam3p provides the t-SNARE function in the vacuolar assembly in A. thaliana.
液泡是植物和真菌细胞中的一个大间隔区。酿酒酵母的VAM3基因编码一种液泡组装所需的与 syntaxin 相关的蛋白质。对一个设计用于在酿酒酵母中表达的拟南芥 cDNA 文库进行筛选，以寻找能够互补 Deltavam3 突变体缺陷液泡组装的 cDNA。鉴定出一个编码 33 kDa 蛋白质的 cDNA，该蛋白质与其他 syntaxin 具有结构相似性。AtVAM3（AtVam3p）的产物在包括根、叶、花序茎、花芽和幼嫩角果在内的各种组织中表达。AtVAM3 转录本在分生组织区域的未分化细胞中丰富。AtVam3p 主要分布在 8000×g 沉淀组分中，液泡膜蛋白 H⁺转运无机焦磷酸酶（H⁺-PPase）也分布在该组分中。免疫电子显微镜显示 AtVam3p 定位于液泡膜上的特定区域。我们提出 AtVam3p 在拟南芥的液泡组装中提供 t-SNARE 功能。
