Rapid Protein Degradation of JAZ6-tagged GFP in Yeast with the Induction of the Plant Hormone Jasmonic Acid

Abstract

In biological systems, changing from one state to another can depend on gene repression, induction of new genes, and degradation of previously used proteins. The ability to quickly and inducibly degrade a signal, repressor, or other protein would greatly improve the sensitivity and timing of biological switches. Auxin is a plant hormone involved in nearly every aspect of plant growth and development. In the presence of auxin, auxin receptors induce polyubiquitylation of a targeted protein, leading to degradation by the proteasome. This system has previously been used to create inducible protein degradation in yeast and mammalian cells. However, a parallel system – using jasmonic acid as the small molecule inducer – is also found in plants and has not yet been studied in yeast. The goal of this project is to characterize and study the jasmonic acid responsive pathway to develop a quick, efficient system to control protein stability in yeast. Coranatine insensitive-1 (COI1), the E3 ligase for this pathway, was first transformed in W303 yeast strains. A cloned JAZ6-tagged green fluorescent protein (GFP) was co-transformed into this same W303 yeast strain. An untagged-GFP was then transformed into a W303 yeast strain. Upon confirming that these yeast strains were producing GFP, varying concentration of coronatine (a mimic of jasmonate) and auxin were added to these strains. With the addition of coronatine, degradation of JAZ6-tagged GFP in the yeast strain with COI1 was observed.