title: Recombinant antibody production in Arabidopsis seeds triggers an unfolded protein response.
abstract: Among the many plant-based production systems that are being tested for molecular farming, seeds are very attractive, as they provide a stable environment in which the accumulating recombinant proteins can be stored. However, it is not known exactly how high production levels of recombinant antibodies influence the endogenous transcriptome and proteome of the developing seed. To address this question, we studied the transcriptomic status in developing Arabidopsis (Arabidopsis thaliana) seeds 13 d post anthesis of three transgenic lines, producing varying levels of recombinant VHH or single-chain Fv antibody fragments fused to the human immunoglobulin G1-derived Fc fragment under the control of the β-PHASEOLIN seed-specific promoter. Using genome-wide Tiling arrays, we demonstrated that only a small proportion of the transcriptome was significantly changed in each of the lines compared with the wild type. Strikingly, in all three lines, we found a large overlap of up-regulated genes corresponding to protein folding, glycosylation/modification, translocation, vesicle transport, and protein degradation, suggestive of a state of cellular stress called the unfolded protein response. Moreover, the gene up-regulation amplitude was similar in all three lines. We hypothesize that the production of recombinant antibodies in the endoplasmic reticulum triggers endoplasmic reticulum stress, causing a disturbance of the normal cellular homeostasis.
authors.affiliation: Department of Plant Systems Biology, VIB, B-9052 Ghent, Belgium.
authors.forename: Kirsten
authors.initials: K
authors.lastname: De Wilde
authors.forename: Sylvie
authors.initials: S
authors.lastname: De Buck
authors.forename: Kevin
authors.initials: K
authors.lastname: Vanneste
authors.forename: Ann
authors.initials: A
authors.lastname: Depicker
mesh_terms: D000906:Antibodies / Q000235:genetics* / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D015153:Blotting, Western; D059865:Endoplasmic Reticulum Stress; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D018525:Germination / Q000235:genetics; D006031:Glycosylation; D006801:Humans; D020411:Oligonucleotide Array Sequence Analysis; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000235:genetics; D017510:Protein Folding; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012639:Seeds / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D057127:Single-Chain Antibodies / Q000235:genetics / Q000378:metabolism; D013997:Time Factors; D056811:Unfolded Protein Response
chemical_list: D000906:Antibodies; D011993:Recombinant Fusion Proteins; D057127:Single-Chain Antibodies