The expression of recombinant proteins in plants is a valuable alternative to bioreactors using mammalian cell systems. Ease of scaling, and their inability to host human pathogens, enhance the use of plants to generate complex therapeutic products such as monoclonal antibodies. However, stably transformed plants expressing antibodies normally have a poor accumulation of these proteins that probably arise from the negative positional effects of their flanking chromatin. The induction of boundaries between the transgenes and the surrounding DNA using matrix attachment regions (MAR) and insulator elements may minimize these effects. With the PHB-01 antibody as a model, we demonstrated that the insertion of DNA elements, the TM2 (MAR) and M4 insulator, flanking the transcriptional cassettes that encode the light and heavy chains of the PHB-01 antibody, increased the protein accumulation that remained stable in the first plant progeny. The M4 insulator had a stronger effect than the TM2, with over a twofold increase compared to the standard construction. This effect was probably associated with an enhancer-promoter interference. Moreover, transgenic plants harboring two transcriptional units encoding for the PHB-01 heavy chain combined with both TM2 and M4 elements enhanced the accumulation of the antibody. In summary, the M4 combined with a double transcriptional unit of the heavy chain may be a suitable strategy for potentiating PHB-01 production in tobacco plants.

中文翻译：

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M4绝缘体、TM2基质附着区和重链基因的双拷贝有助于PHB-01抗体在烟草植物中的增强积累。


在植物中表达重组蛋白是使用哺乳动物细胞系统的生物反应器的一个有价值的替代方案。易于扩展且无法容纳人类病原体，增强了植物用于生产单克隆抗体等复杂治疗产品的用途。然而，表达抗体的稳定转化植物通常这些蛋白质的积累较差，这可能是由于其侧翼染色质的负面位置效应所致。使用基质附着区域 (MAR) 和绝缘体元件诱导转基因和周围 DNA 之间的边界可以最大限度地减少这些影响。以 PHB-01 抗体为模型，我们证明在编码 PHB-01 抗体轻链和重链的转录盒侧翼插入 DNA 元件、TM2 (MAR) 和 M4 绝缘子，可以增加蛋白质积累在第一个植物后代中保持稳定。 M4 绝缘子的效果比 TM2 更强，与标准结构相比增加了一倍多。这种效应可能与增强子-启动子干扰有关。此外，含有两个编码PHB-01重链的转录单位以及TM2和M4元件的转基因植物增强了抗体的积累。总之，M4 与重链双转录单位的组合可能是增强烟草植物中 PHB-01 生产的合适策略。