Göritzer Kathrin, Goet Iris, Duric Stella, Maresch Daniel, Altmann Friedrich, Obinger Christian, Strasser Richard
Department of Applied Genetics and Cell Biology, Institute for Plant Biotechnology and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria.
Division of Biochemistry, Department of Chemistry, University of Natural Resources and Life Sciences, Vienna, Austria.
Front Chem. 2020 Apr 22;8:346. doi: 10.3389/fchem.2020.00346. eCollection 2020.
Production of monomeric IgA in mammalian cells and plant expression systems such as is well-established and can be achieved by co-expression of the corresponding light and heavy chains. In contrast, the assembly of dimeric IgA requires the additional expression of the joining chain and remains challenging especially in plant-based systems. Here, we examined factors affecting the assembly and expression of HER2 binding dimeric IgA1 and IgA2m(2) variants transiently produced in . While co-expression of the joining chain resulted in efficient formation of dimeric IgAs in HEK293F cells, a mixture of monomeric, dimeric and tetrameric variants was detected in plants. Mass-spectrometric analysis of site-specific glycosylation revealed that the -glycan profile differed between monomeric and dimeric IgAs in the plant expression system. Co-expression of a single-subunit oligosaccharyltransferase from the protozoan in increased the -glycosylation occupancy at the C-terminal heavy chain tailpiece and changed the ratio of monomeric to dimeric IgAs. Our data demonstrate that -glycosylation engineering is a suitable strategy to promote the formation of dimeric IgA variants in plants.
在哺乳动物细胞和植物表达系统（如……）中生产单体IgA已得到充分证实，可通过共表达相应的轻链和重链来实现。相比之下，二聚体IgA的组装需要额外表达连接链，并且仍然具有挑战性，尤其是在基于植物的系统中。在这里，我们研究了影响在……中瞬时产生的HER2结合二聚体IgA1和IgA2m(2)变体组装和表达的因素。虽然连接链的共表达导致HEK293F细胞中高效形成二聚体IgA，但在植物中检测到单体、二聚体和四聚体变体的混合物。位点特异性糖基化的质谱分析表明，植物表达系统中单体和二聚体IgA的N-聚糖谱不同。来自原生动物……的单亚基寡糖基转移酶在……中的共表达增加了C末端重链尾肽处的N-糖基化占有率，并改变了单体与二聚体IgA的比例。我们的数据表明，N-糖基化工程是促进植物中二聚体IgA变体形成的合适策略。
