mScarlet and split fluorophore mScarlet resources for plasmid-based CRISPR/Cas9 knock-in in .

Fluorescent proteins allow the expression of a gene and the behavior of its protein product to be observed in living animals. The ability to create endogenous fluorescent protein tags via CRISPR genome engineering has revolutionized the authenticity of this expression, and mScarlet is currently our first-choice red fluorescent protein (RFP) for visualizing gene expression . Here, we have cloned versions of mScarlet and split fluorophore mScarlet previously optimized for into the SEC-based system of plasmids for CRISPR/Cas9 knock-in.