Dissertation presented at Faculdade de Ciências e Tecnologia of Universidade Nova de Lisboa to obtain the Degree of Master in BiotecnologyThe use of transgenic plants for the production of recombinant proteins with commercial and pharmaceutical value offers several advantages when compared to the standard systems.
Whole plant systems have potential for studies of the recombinant protein trafficking and suspension cell cultures combine the advantages of plants with the benefits of protein production by cell cultures.
In this master thesis work, Medicago truncatula plants expressing a lipocalin-type human prostaglandin D2 synthase (L-PGDS) were used and the protein trafficking was studied. This study was the first analysis of the production of this protein in this specific plant and the first
study of the subcellular trafficking of this protein in plants. Two production systems were analyzed: whole-plant systems and suspension cell cultures. The presence of the L-PGDS was studied in three different plant organs (leaf, root and seed) and in the cells and cell medium, by Western Blotting and fluorescence and electron microscopy.
The L-PGDS protein appeared to accumulate in different places and patterns depending
on which type of cell it is being produced. Recent work has shown that functional specialization of plant cells in storage organs can influence the subcellular trafficking of recombinant proteins,
so the protein subcellular fate could be different between seeds and leaves of the same transformed plant. It has also been demonstrated that the plant species where the recombinant protein is produced, can alter the trafficking parameters.
Medicago truncatula is, thus, a promising system for the production of recombinant
proteins. The initial results obtained in this study could contribute to future studies and development in Molecular Farming
