A complex fruit-specific type-2 ribosome-inactivating protein from elderberry (Sambucus nigra) is correctly processed and assembled in transgenic tobacco plants.
Fruits of elderberry (Sambucus nigra) express small quantities of a type-2 ribosome-inactivating protein with an exclusive specificity towards the NeuAc(alpha2,6)Gal/GalNAc disaccharide and a unique molecular structure typified by the occurrence of a disulfide bridge between the B-chains of two adjacent protomers. A cDNA clone encoding this so-called Sambucus nigra fruit specific agglutinin I (SNA-If) was isolated and expressed in tobacco (Samsun NN) under the control of the 35S cauliflower mosaic virus promoter. Characterization of the purified protein indicated that the recombinant SNA-If from tobacco leaves has the same molecular structure and biological activities as native SNA-If from elderberry fruits, demonstrating that transgenic tobacco plants are fully capable of expressing and correctly processing and assembling a type-2 ribosome-inactivating protein with a complex molecular structure. None of the transformants showed a phenotypic effect, indicating that the ectopically expressed SNA-If does not affect the viability of the tobacco cells. Bioassays further demonstrated that none of the transgenic lines exhibited a decreased sensitivity to infection with tobacco mosaic virus suggesting that the elderberry type-2 RIP SNA-If does not act as an antiviral agent in planta.
Chen
Ying
Y
Laboratory for Phytopathology and Plant Protection, Katholieke Universiteit Leuven, Belgium.
Vandenbussche
Frank
F
Rougé
Pierre
P
Proost
Paul
P
Peumans
Willy J
WJ
Van Damme
Els J M
EJ
D000595:Amino Acid Sequence; D018076:DNA, Complementary / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D005638:Fruit / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D006031:Glycosylation; D037102:Lectins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009699:N-Glycosyl Hydrolases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D009928:Organ Specificity; D010935:Plant Diseases / Q000821:virology; D037121:Plant Lectins; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D054788:Ribosome Inactivating Proteins; D054790:Ribosome Inactivating Proteins, Type 2; D027924:Sambucus nigra / Q000737:chemistry*; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism*; D014027:Tobacco Mosaic Virus / Q000472:pathogenicity
D018076:DNA, Complementary; D037102:Lectins; D037121:Plant Lectins; D010940:Plant Proteins; D011994:Recombinant Proteins; D054790:Ribosome Inactivating Proteins, Type 2; C050600:Sambucus nigra lectins; D009699:N-Glycosyl Hydrolases; D054788:Ribosome Inactivating Proteins