Impact of the over expression of plant transmenbrane bZIP transcription factors on the synthesis of antibodies in N. benthamiana leaves

MAZZINI, FLAVIA NOELIA; PETRUCCELLI, SILVANA*

Varadero

Congreso; Biotecnologia Habana; 2017

Centro de Ingeniería Genética y Biotecnología (CIGB)

Plants are an emerging platform for the production of valuable proteins with numerous products on the market. A wide variety of strategies have been developed to improve plant as factories, but the manipulation of bottlenecks that limit the production of proteins in the secretory pathway has not been explored. The aim of this work was to study the ability of plant transmembrane bZIP transcription factors, orthologous of the mammalian X-box binding protein 1 (XBP1), to increase foreign secretory protein yields. To this end, N. benthamiana leaves were infiltrated with different combinations of Agrobacterium tumefaciens carrying the genes encoding for the reporter and effector proteins and the amount of reporter proteins were quantified 5-6 days post infiltration (dpi). Three effector constructs were evaluated: the full length bZIP17, bZIP60 and a truncated version of bZIP60 without the transmembrane domain (bZIP60ΔC). First, we analyzed the ability of the effectors to modify the synthesis of an endoplasmic reticulum targeted beta-glucuronidase (ER-GUS). GUS activity was higher in leaves infiltrated with bZIP60ΔC and bZIP17 than control mock leaves. The combination of effectors produced a decrease in GUS activity. Besides, the impact of the effectors on accumulation of the reporter ER-GFP was studied by immunoblot and consistently also the higher amount of ER-GFP was detected in the leaf extract infiltrated with bZIP60ΔC. Finally, the full length monoclonal antibody (mAb) 14D9 and a single chain antibody 2G3 (scFv) sorted to ER were also produced in leaves co-agroinfiltrated with the different effectors. A 50% increase of both mAb and scFv yields was detected in leaves infiltrated with bZIP60ΔC. Adittionaly, antibodies preserved their integrity In conclusion, this work demonstrated that bZIP60ΔC increases the yield of different ER targeted proteins.