The dynamic behavior of storage organelles in developing cereal seeds and its impact on the production of recombinant proteins

Abstract

Cereal endosperm is a highly differentiated tissue containing specialized organelles for the accumulation of storage proteins, which are ultimately deposited either within protein bodies derived from the endoplasmic reticulum, or in protein storage vacuoles (PSVs). During seed maturation endosperm cells undergo a rapid sequence of developmental changes, including extensive reorganization and rearrangement of the endomembrane system and protein transport via several developmentally regulated trafficking routes. Storage organelles have been characterized in great detail by the histochemical analysis of fixed immature tissue samples. More recently, in vivo imaging and the use of tonoplast markers and fluorescent organelle tracers have provided further insight into the dynamic morphology of PSVs in different cell layers of the developing endosperm. This is relevant for biotechnological applications in the area of molecular farming because seed storage organelles in different cereal crops offer alternative subcellular destinations for the deposition of recombinant proteins that can reduce proteolytic degradation, allow control over glycan structures and increase the efficacy of oral delivery. We discuss how the specialized architecture and developmental changes of the endomembrane system in endosperm cells may influence the subcellular fate and post-translational modification of recombinant glycoproteins in different cereal species.

Efficacy of transgenic rice containing human interleukin-10 in experimental mouse models of colitis and pollen allergy

“…Our results further stress the advantages of rice endosperm as a production platform and efficient mucosal delivery vehicle for therapeutic peptides and proteins (Arcalis et al 2014;Takagi et al 2010;Takaiwa 2013;Yang et al 2012). In light of future clinical applications, un-powdered and cooked rice might be a suitable formulation for human consumption.…”

The increasing value of plant-made proteins

“…The genetic background of the production host is an important factor that can be influenced by crossing, breeding and selection [24], but targeted engineering of the host genome can also be used to reduce the accumulation of endogenous storage proteins, thus providing further capacity for the storage of recombinant proteins [25]. A deeper understanding of recombinant protein storage and protein quality control in the endomembrane system will promote strategies such as the induction of ectopic storage organelles [26–29]. …”

Antibodies from plants for bionanomaterials

“…20 Platforms based on seed storage also combine perfectly with strategies that facilitate downstream processing and make it more cost-effective by using protein domains that form high-molecularweight or nanomaterial structures, such as elastin-like peptides, hydrophobins, or peptides that promote the formation of protein bodies. 3,4,[89][90][91][92] However, in reality, the reluctance of big industry players to invest in a relatively untested (and unsupported) new technology, and public hostility to the open-field cultivation of GM crops in Europe, has slowed down the fulfillment of these promises. But the development of transient gene expression systems 56,[93][94][95] has added speed to the panel of advantages offered by molecular farming in plants and the promises seem to be within reach once again.…”