A pollen-specific polygalacturonase from lily is related to major grass pollen allergens
- 作者：J.-Y. Chiang ; N. Balic ; S.-W. Hsu ; C.-Y. Yang ; C.-W. Ko ; Y.-F. Hsu ; I. Swoboda ; C.-S. Wang
- 关键词：Allergen ; Gene expression ; IgE cross-reactivity ; Lilium ; longiflorum ; Pollen-specific ; Polygalacturonase
- 刊名：Plant Physiology and Biochemistry
- 出版年：2006
- 期刊代码：87_09819428
- 类别：abs
- 出版时间：November-December 2006
- 卷：44
- 期：11-12
- 页码：743-751
- 文件大小：689 K
摘要
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.