UASt sequences regulate expression of a split-GFP sensor that can be used to monitor cholesterol and endoplasmic reticulum (ER) contact. The construct contains a dicistronic transcription unit that encodes two open reading frames (ORFs) separated by a 2A linker (this promotes separate translation of each protein). The first ORF comprises Tag:D4H(Y415A.A463W) fused to seven tandem copies of the spGFP11 split fluorescent protein fragment, followed by Tag:V5. The second ORF comprises Tag:FLAG fused to spGFP1-10 followed by a Tag:ER(cb5) ER targeting motif.