Chiang J-Y, Balic N, Hsu S-W, Yang C-Y, Ko C-W, Hsu Y-F, Swoboda I, Wang C-S
Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan, ROC.
Plant Physiol Biochem. 2006 Nov-Dec;44(11-12):743-51. doi: 10.1016/j.plaphy.2006.10.005. Epub 2006 Oct 17.
A pollen-specific gene from lily (Lilium longiflorum Thunb. cv. Snow Queen), designated LLP-PG, was characterized. Southern blots of lily genomic DNA indicated that LLP-PG is a member of a small gene family. A thorough sequence analysis revealed that the LLP-PG gene is interrupted by two introns and encodes a protein of 413 amino acids, with a calculated molecular mass of 44 kDa, and a pI of 8.1. Evaluation of the hydropathy profile showed that the protein has a hydrophobic segment at the N-terminus, indicating the presence of a putative signal peptide. A sequence similarity search showed a significant homology of the encoded protein to pollen polygalacturonases (PGs) from various plant species and to an important group (group 13) of grass pollen allergens. The LLP-PG transcript is pollen-specific and it accumulates only at the latest stage during pollen development, in the mature pollen. In contrast to other "late genes" LLP-PG transcript can neither be induced by abscisic acid (ABA) nor by dehydration. Immunoblot analyses of pollen protein extracts from lily, timothy grass and tobacco with IgG antibodies directed against LLP-PG and against the timothy grass pollen allergen, Phl p 13, indicated that lily LLP-PG shares surface-exposed epitopes with pollen PGs from monocotyledonous and dicotyledonous plants. Enzyme-linked immunosorbent assay (ELISA) analyses and inhibition ELISA assays with patients' IgE demonstrated a very low IgE reactivity of lily rLLP-PG and a lack of cross-reactivity between rLLP-PG and the timothy grass pollen allergen, rPhl p 13. These data demonstrated that despite the significant sequence homology and the conserved surface-exposed epitopes LLP-PG represents a low-allergenic member of pollen PGs.
对来自百合（麝香百合栽培品种“雪皇后”，Lilium longiflorum Thunb. cv. Snow Queen）的一个花粉特异性基因进行了表征，该基因命名为LLP - PG。百合基因组DNA的Southern杂交分析表明LLP - PG是一个小基因家族的成员。全面的序列分析显示，LLP - PG基因被两个内含子打断，编码一个由413个氨基酸组成的蛋白质，计算分子量为44 kDa，等电点为8.1。对亲水性图谱的评估表明，该蛋白质在N端有一个疏水片段，表明存在一个假定的信号肽。序列相似性搜索显示，所编码的蛋白质与来自各种植物物种的花粉多聚半乳糖醛酸酶（PGs）以及禾本科花粉过敏原的一个重要类别（第13组）具有显著同源性。LLP - PG转录本是花粉特异性的，并且仅在花粉发育的最晚阶段，即成熟花粉中积累。与其他“晚期基因”不同，LLP - PG转录本既不能被脱落酸（ABA）诱导，也不能被脱水诱导。用针对LLP - PG和梯牧草花粉过敏原Phl p 13的IgG抗体对百合、梯牧草和烟草的花粉蛋白提取物进行免疫印迹分析表明，百合LLP - PG与单子叶和双子叶植物的花粉PGs具有表面暴露的表位。用患者的IgE进行酶联免疫吸附测定（ELISA）分析和抑制ELISA测定表明，百合重组LLP - PG的IgE反应性非常低，并且重组LLP - PG与梯牧草花粉过敏原重组Phl p 13之间缺乏交叉反应性。这些数据表明，尽管存在显著的序列同源性和保守的表面暴露表位，但LLP - PG代表了花粉PGs中的一个低过敏原成员。
