Targeted knockouts of Physcomitrella lacking plant-specific immunogenic N-glycans.
Using plants as production factories for therapeutic proteins requires modification of their N-glycosylation pattern because of the immunogenicity of plant-specific sugar residues. In an attempt towards such humanization, we disrupted the genes for alpha1,3-fucosyltransferase and beta1,2-xylosyltransferase in Physcomitrella patens by homologous recombination. The single Deltafuc-t and Deltaxyl-t plants, as well as the double knockout, lacked transcripts of the corresponding genes, but did not differ from the wild-type moss in morphology, growth, development, and ability to secrete a recombinant protein, the human vascular endothelial growth factor VEGF(121), into the culture medium. N-Glycan analysis, however, revealed the absence of 1,3-fucosyl and/or 1,2-xylosyl residues, respectively. Therefore, the modifications described here represent the key step towards the generation of moss lines suitable for the production of plant-made glycosylated biopharmaceuticals with nonallergenic N-glycans.
Koprivova
Anna
A
University of Freiburg, Plant Biotechnology, Schaenzlestr. 1, 79104 Freiburg, Germany.
Stemmer
Christian
C
Altmann
Friedrich
F
Hoffmann
Axel
A
Kopriva
Stanislav
S
Gorr
Gilbert
G
Reski
Ralf
R
Decker
Eva L
EL