Identification, expression, and evolutionary analyses of plant lipocalins
Identification, expression, and evolutionary analyses of plant lipocalins
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DOI：
10.1104/pp.105.070466
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发表时间：
2005-12-01
期刊：
影响因子：
7.4
通讯作者：
Sarhan, F
中科院分区：
文献类型：
--
作者：
Charron, JBF;Ouellet, F;Sarhan, F
脂质运载蛋白是一组在细菌、无脊椎动物和脊椎动物中已被表征的蛋白质。然而，对植物脂质运载蛋白知之甚少。我们以前报道了第一个真正的植物脂质运载蛋白的克隆。在这里，我们报告的识别和表征的植物脂质运载蛋白和脂质运载蛋白样蛋白的数据挖掘，表达研究，细胞定位和系统发育分析的综合方法。植物脂质运载蛋白可分为两类：温度诱导的脂质运载蛋白（TILS）和叶绿体脂质运载蛋白（CHLS）。此外，紫黄质脱环氧化酶（VDE）和玉米黄质环氧化酶（ZEP）可归类为脂笼蛋白样蛋白。CHL、VDE和ZEP具有将它们靶向叶绿体的转运肽。另一方面，TILs不显示任何靶向肽，但定位研究表明，蛋白质存在于质膜上。通过定量实时PCR的表达分析表明，小麦（Triticum aestivum）脂质运载蛋白和脂质运载蛋白样蛋白的表达与非生物胁迫反应相关，并与植物的能力，发展抗冻性。为了支持这种相关性，数据挖掘显示，脂质运载蛋白存在于耐干燥的红藻条斑紫菜和耐低温的海洋酵母Debaryomyces hansenii中，这表明可能与耐胁迫生物有关。考虑到植物脂质运载蛋白的性质，组织特异性，对温度胁迫的反应，以及它们与绿色叶片的叶绿体和质膜的关联，我们假设光合系统对温度胁迫的保护功能。系统发育分析表明，在高等植物中的TIL脂质运载蛋白成员可能是从一个原始的单细胞真核生物中存在的细菌基因遗传。另一方面，CHLs，VDE和ZEP可能是在叶绿体起源的蓝藻内共生体形成后从蓝藻祖先基因进化而来的。
Lipocalins are a group of proteins that have been characterized in bacteria, invertebrate, and vertebrate animals. However, very little is known about plant lipocalins. We have previously reported the cloning of the first true plant lipocalins. Here we report the identification and characterization of plant lipocalins and lipocalin-like proteins using an integrated approach of data mining, expression studies, cellular localization, and phylogenetic analyses. Plant lipocalins can be classified into two groups, temperature-induced lipocalins (TILs) and chloroplastic lipocalins (CHLs). In addition, violaxanthin de-epoxidases (VDEs) and zeaxanthin epoxidases (ZEPs) can be classified as lipocalin-like proteins. CHLs, VDEs, and ZEPs possess transit peptides that target them to the chloroplast. On the other hand, TILs do not show any targeting peptide, but localization studies revealed that the proteins are found at the plasma membrane. Expression analyses by quantitative real-time PCR showed that expression of the wheat (Triticum aestivum) lipocalins and lipocalin-like proteins is associated with abiotic stress response and is correlated with the plant's capacity to develop freezing tolerance. In support of this correlation, data mining revealed that lipocalins are present in the desiccation-tolerant red algae Porphyra yezoensis and the cryotolerant marine yeast Debaryomyces hansenii, suggesting a possible association with stress-tolerant organisms. Considering the plant lipocalin properties, tissue specificity, response to temperature stress, and their association with chloroplasts and plasma membranes of green leaves, we hypothesize a protective function of the photosynthetic system against temperature stress. Phylogenetic analyses suggest that TIL lipocalin members in higher plants were probably inherited from a bacterial gene present in a primitive unicellular eukaryote. On the other hand, CHLs, VDEs, and ZEPs may have evolved from a cyanobacterial ancestral gene after the formation of the cyanobacterial endosymbiont from which the chloroplast originated.