RTE1 and RTE2 Interaction Studies Using Split Ubiquitin
Protein interaction is crucial for cellular life. Interaction studies that identify interactors with previously characterized or novel proteins can help to identify functions for genes of interest. To further characterize the role of Arabidposis thaliana RTE1 and RTH, I am performing split-ubiquitin interaction screens in yeast against an Arabidopsis cDNA library to identify interactors of RTE1 and RTH. These experiments will help to support and refine current hypotheses and/or shed light upon potential funcrtions of RTE1 and RTH.
Undergraduate Work: Studying RTE1 in the model system C. elegans
 The goal of my research is to uncover potential functions of a recently isolated novel gene of unknown biochemical function present in all multicellular organisms. This research originated from the discovery of REVERSION TO ETHYLENE SENSITIVITY 1 (RTE1) in the flowering plant Arabidopsis thaliana . The RTE1 gene was identified as a genetic suppressor of a mutant ethylene receptor involved in ethylene signaling in plants. However, functional characterization of RTE1 in A. thaliana has been complicated by the presence of a second RTE gene in the Arabidopsis genome. Since RTE is present in a single copy in animals, we chose to pursue functional analysis of the Caenorhabditis elegans RTE homolog. The fact that the ethylene receptors in plants require a copper co-factor in order to bind ethylene, led to the hypothesis that RTE1 may be involved in homeostasis or transport of copper ions.
Though copper is an essential co-factor for a variety of enzymes, it is also extremely harmful to cells and in nematodes can cause severe morphological defects including reduced girth, shortened body length and reduced viability. To test the copper hypothesis in C. elegans,RTE1 dsRNA-fed nematodes were grown in media supplemented with toxic levels of copper and examined for changes in toxic response. Measurements of body length suggest that knockdown of RTE1 expression by RNAi causes a significantly increased tolerance to toxic levels of copper (but not cadmium). GFP experiments support that expression of loc-1 appears to be constitutive in all cells as predicted by the finding that the loc-1 transcript is trans-spliced to SL1 and is likely to be the first member of an operon. RTE1 research provides the first demonstration of an altered copper response in the absence of an RTE1-related gene in any organism and will be extremely useful for unlocking the function of RTE1-related genes in all organisms.
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