Production of recombinant gelatin in barley

Gelatin, derived from collagen, is an attractive mammalian protein to be used as model for the commercial production of complex heterologous proteins in plants. Collagen requires post-translational modifications and triple helical assembly. The availability of a plant-derived product will provide a safer, more homogeneous product than the current animal-derived material. The aim of the project is to develop a production system for the accumulation of recombinant gelatin and of recombinant collagen for conversion to gelatin using barley seed. Two strong transcriptional promoters will be used for production of recombinant collagen and gelatin in transgenic barley during germination and maturation of barley seeds. The 5'-end of the Cocksfoot mottle virus (CfMV; genus Sobemovirus) genomic RNA sequence, called CfMV -element, has been shown to enhance recombinant protein synthesis in barley. The -element will be used to study whether accumulation levels of complex mammalian proteins can be further increased, using collagen and gelatin as models that will serve as basis for exploring the expression of other complex proteins and the commercial production of recombinant gelatin from plants. In order to achieve proper post-translational modification, mammalian prolyl-4-hydroxylase will be co-expressed with collagen in barley seeds.