MORE | Spring 2020

Cas9 Mediated Adenosine Transient Reporter for Editing Enrichment

CRISPR/Cas9 systems can be used to edit induced pluripotent stem cells to create nearly any genomic edit for disease-modeling. However, there is no readily available phenotype to enrich for edited cells. Cas9-Mediated Adenosine Transient Reporter for Editing Enrichment (CasMasTREE) was created to act as a fluorescent reporter for editing featuring a mCherry and green fluorescent protein separated by a stop codon. Upon successful base-editing of the stop codon, cells fluoresce red and green. By sorting for dual-positive cells, CasMasTREE produced singleplex editing up to 94% and multiplex editing up to 94% at genomic loci in HEK293T and stem cells.