Sakr S, Noubahni M, Bourbouloux A, Riesmeier J, Frommer W B, Sauer N, Delrot S
Laboratoire de Physiologie et Biochimie Végétales, ERS CNRS 6099, Université de Poitiers, France.
Biochim Biophys Acta. 1997 Dec 4;1330(2):207-16. doi: 10.1016/s0005-2736(97)00169-7.
The activity and the expression of sucrose, hexose and amino acid transporters were studied with fresh, cut or aged tissues and plasma membrane vesicles (PMV) of mature sugar beet (Beta vulgaris L.) leaves. Cutting and ageing both induced an increase of the transcripts coding for sucrose transporters and hexose transporters. No significant effect could be detected on the amino acid transporter transcripts with the probe used (aap1). A polyclonal serum directed against the Arabidopsis thaliana sucrose transporter (AtSUC1) reacted with a 42 kDa band of the sugar beet PMV, confirming previous biochemical identification of this band as a sucrose transporter. ELISA assays run with microsomal fractions and PMV using the AtSUC1 sucrose transporter probe indicated that ageing, and to a lesser extent cutting, increased the amount of sucrose transporter present in the plasma membrane. However, while cutting strongly stimulated proton-motive force driven uptake of sucrose in PMV, ageing only resulted in a slight stimulation. These data give evidence for transcriptional, post-transcriptional and post-translational controls of the activity of the sucrose transporter by mechanical treatments. Proton-motive force driven uptake of 3-O-methylglucose and valine in PMV was strongly stimulated in PMV from aged tissues, although previous data had shown that cutting did not affect theses processes. Therefore, the plant cells possess various levels of control mechanisms that allow them to regulate fluxes of the main assimilates across the plasma membrane when their natural environment is directly or indirectly altered.
利用新鲜、切割或老化的组织以及成熟甜菜（Beta vulgaris L.）叶片的质膜囊泡（PMV），研究了蔗糖、己糖和氨基酸转运蛋白的活性及表达。切割和老化均诱导了编码蔗糖转运蛋白和己糖转运蛋白的转录本增加。使用所采用的探针（aap1）未检测到对氨基酸转运蛋白转录本有显著影响。一种针对拟南芥蔗糖转运蛋白（AtSUC1）的多克隆血清与甜菜PMV的一条42 kDa条带发生反应，证实了先前将该条带生化鉴定为蔗糖转运蛋白。使用AtSUC1蔗糖转运蛋白探针，对微粒体组分和PMV进行的ELISA分析表明，老化以及程度较轻的切割增加了质膜中蔗糖转运蛋白的量。然而，虽然切割强烈刺激了PMV中质子动力驱动的蔗糖摄取，但老化仅导致轻微刺激。这些数据证明了机械处理对蔗糖转运蛋白活性的转录、转录后和翻译后控制。老化组织的PMV中质子动力驱动的3 - O - 甲基葡萄糖和缬氨酸摄取受到强烈刺激，尽管先前的数据表明切割不影响这些过程。因此，当植物细胞的自然环境直接或间接改变时，它们拥有各种水平的控制机制，使其能够调节主要同化物跨质膜的通量。
