Systems Biology: Pathway Engineering platforms

Natural products have played a very prominent role in the treatment of human disease throughout history [Newman, Nat Prod Rep 2000], as drugs or as starting materials for pharmaceutical synthetic chemistry. However, these efforts can encounter insurmountable obstacles because of chemical complexity issues, low yields, high economic cost and oftentimes-nasty environmental consequences. Synthetic biology and metabolic engineering of whole pathways for the heterologous production of natural products can deliver effective solutions and consequently methods to develop recombinant microorganisms capable of producing chemically challenging biological materials are greatly needed [Chang et al, Nature Chem Biol 2006]. With a projected market volume in excess of €30 billion [Demain et al, Biotechnol Adv 2009], metabolic engineering will pave the way for more sustainable, greener and cheaper medicines.

S. cerevisiae is at the forefront of this emerging field with success stories including the production of taxol and artemisinic acid. It is a genetically well-characterized and tractable organism into which reconstruction of complete biosynthetic pathways is possible and permits large-scale production by fermentation of highly complex small-molecule scaffolds starting from inexpensive carbon and nitrogen supplies.

The MultiYeast system developed at the Vega lab represents a unique addition to the pathway engineer’s toolbox. Powered by the ACEMBL technology developed by the Berger lab, MultiYeast allows rapid and scalable assembly of unrestricted multigene constructs and therefore can accommodate the large number of genes that are typically required for a fully functional metabolic pathway. In contrast to other available methods for pathway engineering, MultiYeast enables cloning different gene modules in separate acceptor and donor plasmids thereby allowing the rapid re-evaluation of experiments when additional gene modules are appended to a base pathway. MultiYeast can contribute to pathway engineering in S. cerevisiae by making feasible the cloning of complex multigene constructs while simultaneously allowing the factoring out of components.