UNS: A Novel Cell Selection System Using Evolved, Natural-Product Responsive Caspases

University Of Massachusetts Amherst, Amherst MA

Investigators

Abstract

1511367 Hardy, Jeanne A. Various plants make many different chemicals that are of use to human beings in personal healthcare products, neutraceuticals, flavors and fragrances, oils and fats and other high-value foods and pharmaceutical ingredients. In this project it is proposed to increase productivity of plant cell cultures by eliminating the non-producing cells and by keeping the high-producing cells alive with the help of a mammalian protein. This cell-killing protein has a binding site that can be manipulated so that it binds a specific chemical. When that compound binds it inactivates the protein. In cells that make lots of the desired chemical, the cell-killing protein is turned off and cells remain alive. This system will first be developed for plant culture based production of Taxol, a chemotherapy drug. The approach is expected to be applicable to many valuable chemicals produced by plant cells. Plant natural products represent a promising sector of rare and unique chemical entities impacting healthcare, energy, agriculture, food and nutraceuticals. Production and supply of desirable natural products is often challenging due to their chemical complexity, incompletely characterized biosynthetic pathways and prohibitive numbers of steps in their synthetic preparation. The synthesis of compounds with plant cell hosts often is suboptimal due to low production levels and cellular heterogeneity, with some cells producing high levels and other cells producing no product. In this project a completely novel approach has been designed that enables selection of high-producing cells from heterogeneous plant cultures. This approach relies on the finding that particular mammalian proteases sentence plant cells to death. A fluorescent reporter will be used to engineer an existing protease allosteric site to recognize and be inhibited by paclitaxel (Taxol). This protease that can be inhibited by Taxol, will selectively kill non-paclitaxel producing cells, while leaving productive cells intact. The approach likely will be useful not only for the production of Taxol but for a broad range of plant culture systems. This award by the Biotechnology and Biochemical Engineering Program of the CBET Division is co-funded by the Cellular Dynamics and Function Program of the Division of Molecular and Cellular Biology.