Capel J, Jarillo J A, Salinas J, Martínez-Zapater J M
Departamento de Biología Molecular y Virología Vegetal, Instituto Nacional de Investigaciones Agrarias, Madrid, Spain.
Plant Physiol. 1997 Oct;115(2):569-76. doi: 10.1104/pp.115.2.569.
We have characterized two related cDNAs (RCI2A and RCI2B) corresponding to genes from Arabidopsis thaliana, the expression of which is transiently induced by low, nonfreezing temperatures. RCI2A and RCI2B encode small (54 amino acids), highly hydrophobic proteins that bear two potential transmembrane domains. They show similarity to proteins encoded by genes from barley (Hordeum vulgare L.) and wheatgrass (Lophophyrum elongatum) that are regulated by different stress conditions. Their high level of sequence homology (78%) and their genomic location in a single restriction fragment suggest that both genes originated as a result of a tandem duplication. However, their regulatory sequences have diverged enough to confer on them different expression patterns. Like most of the cold-inducible plant genes characterized, the expression of RCI2A and RCI2B is also promoted by abscisic acid (ABA) and dehydration but is not a general response to stress conditions, since it is not induced by salt stress or by anaerobiosis. Furthermore, low temperatures are able to induce RCI2A and RCI2B expression in ABA-deficient and -insensitive genetic backgrounds, indicating that both ABA-dependent and -independent pathways regulate the low-temperature responsiveness of these two genes.
我们已鉴定出两个与拟南芥基因对应的相关cDNA（RCI2A和RCI2B），其表达受低温、非冰冻温度短暂诱导。RCI2A和RCI2B编码小的（54个氨基酸）、高度疏水的蛋白质，带有两个潜在的跨膜结构域。它们与大麦（Hordeum vulgare L.）和冰草（Lophophyrum elongatum）中受不同胁迫条件调控的基因所编码的蛋白质相似。它们高水平的序列同源性（78%）以及在单个限制片段中的基因组定位表明这两个基因起源于串联重复。然而，它们的调控序列已经分化到足以赋予它们不同的表达模式。与大多数已鉴定的冷诱导植物基因一样，RCI2A和RCI2B的表达也受脱落酸（ABA）和脱水促进，但不是对胁迫条件的普遍反应，因为它不受盐胁迫或厌氧诱导。此外，低温能够在ABA缺陷和不敏感的遗传背景中诱导RCI2A和RCI2B表达，表明ABA依赖和非依赖途径均调控这两个基因的低温反应性。
