The genes that I am currently working on are essential and therefore when they are deleted by traditional means the result is a lethal mutant. Therefore, I am interested in performing either conditional or site specific knockdown only in my cell type of interest. I have been attempting to express dominant negative versions of my proteins under a cell type specific promoter with varying degrees of success. Does anyone know if there is a reason why dominant negative proteins would not exhibit efficient knockdown in C. elegans? Additionally, does anyone know if conditional knockout via the Cre-loxp system is something that can be done in C. elegans? Finally, has anyone attempted to express snapback RNAi constructs in C. elegans neurons(which are typically refractory to RNAi) with any success? Any thoughts/suggestions would be greatly appreciated.