A pollen-specific polygalacturonase from lily is related to major grass pollen allergens.
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.
Chiang
J-Y
JY
Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan, ROC.
Balic
N
N
Hsu
S-W
SW
Yang
C-Y
CY
Ko
C-W
CW
Hsu
Y-F
YF
Swoboda
I
I
Wang
C-S
CS
D000485:Allergens / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology; D001483:Base Sequence; D003429:Cross Reactions / Q000276:immunology; D000939:Epitopes / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology; D018506:Gene Expression Regulation, Plant / Q000502:physiology*; D006801:Humans; D006967:Hypersensitivity / Q000201:enzymology / Q000276:immunology; D007073:Immunoglobulin E / Q000276:immunology; D007074:Immunoglobulin G / Q000276:immunology; D027762:Lilium / Q000201:enzymology* / Q000235:genetics / Q000276:immunology; D008969:Molecular Sequence Data; D031784:Phleum / Q000201:enzymology / Q000235:genetics / Q000276:immunology; D010940:Plant Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology; D011058:Pollen / Q000201:enzymology* / Q000235:genetics / Q000276:immunology; D011096:Polygalacturonase / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology; D017385:Sequence Homology; D014026:Nicotiana / Q000201:enzymology / Q000235:genetics / Q000276:immunology
D000485:Allergens; D000939:Epitopes; D007074:Immunoglobulin G; D010940:Plant Proteins; D011994:Recombinant Proteins; D007073:Immunoglobulin E; D011096:Polygalacturonase