Abstract
Alteration of the lipid composition of biological membranes interferes with their function and can cause tissue damage by triggering apoptosis. Upon lipid bilayer stress, the endoplasmic reticulum mounts a stress response that is similar to the unfolded protein response. However, only a few genes are known to regulate lipid bilayer stress. Here, we performed a suppressor screen that combined the auxin-inducible degradation (AID) system with conventional RNAi in C. elegans to identify members of the lipid bilayer stress response. AID-mediated knockdown of the mediator MDT-15, a protein required for the upregulation of fatty acid desaturases, caused activation of a lipid bilayer stress sensitive reporters. We screened through almost all C. elegans kinases and transcription factors using RNAi by feeding. We report the identification of 8 genes that have not been implicated previously with lipid bilayer stress before in C. elegans. These suppressor genes include skn-1/NRF1,2,3 and let-607/CREB3. Our candidate suppressor genes suggest a network of transcription factors and the integration of multiple tissues for a centralized lipotoxicity response in the intestine. Additionally, we propose and demonstrate the proof-of-concept for combining AID and RNAi as a new screening strategy.
