TISSUE-SPECIFIC EXPRESSION OF A GENE ENCODING A CELL WALL-LOCALIZED LIPID TRANSFER PROTEIN FROM ARABIDOPSIS
TISSUE-SPECIFIC EXPRESSION OF A GENE ENCODING A CELL WALL-LOCALIZED LIPID TRANSFER PROTEIN FROM ARABIDOPSIS
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DOI：
10.1104/pp.105.1.35
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发表时间：
1994-05-01
期刊：
影响因子：
7.4
通讯作者：
SOMERVILLE, C
中科院分区：
文献类型：
--
作者：
THOMA, S;HECHT, U;SOMERVILLE, C
植物非特异性脂质转移蛋白（LTP）的特点是能够在体外刺激磷脂在膜间的转移。然而，由于这些蛋白质通常位于质膜外，因此它们不太可能在体内具有类似的作用。作为鉴定这些蛋白质功能的一步，已克隆了拟南芥中的几个LTP基因之一，并通过分析含有LTP启动子-GUS融合体的转基因植物中β-葡萄糖醛酸酶（GUS）活性的组织特异性和原位mRNA定位来研究该基因的表达模式。LTP 1启动子在胚胎、维管组织、子叶、茎分生组织和托叶的原胚层细胞中发育早期就有活性。在成年植株中，该基因在幼叶和茎的表皮细胞中表达。在花中，在所有发育中的花序和花器官原基的表皮、角果和胚珠外壁的表皮、成熟花的柱头、花瓣尖端和花蜜腺以及成熟角果的花瓣/萼片分离区中观察到表达。GUS活性在保卫细胞，侧根，花粉粒，叶维管组织，托叶和蜜腺的内部细胞的存在下，没有被证实的原位杂交，支持以前的观察表明，报告基因是受人为表达。这些结果与LTP 1基因产物在扩张表皮细胞和某些分泌组织的细胞壁中亲脂性物质的分泌或沉积的某些方面的作用一致。LTP 1启动子区含有与苯丙素类生物合成途径中基因的推定调控元件同源的序列，表明LTP 1基因的表达可能受到与苯丙素类途径中基因相同或相似机制的调控。
Nonspecific lipid transfer proteins (LTPs) from plants are characterized by their ability to stimulate phospholipid transfer between membranes in vitro. However, because these proteins are generally located outside of the plasma membrane, it is unlikely that they have a similar role in vivo. As a step toward identifying the function of these proteins, one of several LTP genes from Arabidopsis has been cloned and the expression pattern of the gene has been examined by analysis of the tissue specificity of beta-glucuronidase (GUS) activity in transgenic plants containing LTP promoter-GUS fusions and by in situ mRNA localization. The LTP1 promoter was active early in development in protoderm cells of embryos, vascular tissues, lignified tips of cotyledons, shoot meristem, and stipules. In adult plants, the gene was expressed in epidermal cells of young leaves and the stem. In flowers, expression was observed in the epidermis of all developing inflorescence and flower organ primordia, the epidermis of the siliques and the outer ovule wall, the stigma, petal tips, and floral nectaries of mature flowers, and the petal/sepal abscission zone of mature siliques. The presence of GUS activity in guard cells, lateral roots, pollen grains, leaf vascular tissue, and internal cells of stipules and nectaries was not confirmed by in situ hybridizations, supporting previous observations that suggest that the reporter gene is subject to artifactual expression. These results are consistent with a role for the LTP1 gene product in some aspect of secretion or deposition of lipophilic substances in the cell walls of expanding epidermal cells and certain secretory tissues. The LTP1 promoter region contained sequences homologous to putative regulatory elements of genes in the phenylpropanoid biosynthetic pathway, suggesting that the expression of the LTP1 gene may be regulated by the same or similar mechanisms as genes in the phenylpropanoid pathway.