Using CRISPR-Cas9 to Study ERK Signaling in Drosophila.

Genome engineering using the clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR associated nuclease 9 (Cas9) technology is revolutionizing biomedical research. CRISPR-Cas9 enables precise editing of genes in a wide variety of cells and organisms, thereby accelerating molecular studies via targeted mutagenesis, epitope tagging, and other custom genetic modifications. Here, we illustrate the CRISPR-Cas9 methodology by focusing on Capicua (Cic), a nuclear transcriptional repressor directly phosphorylated and inactivated by ERK/MAPK. Specifically, we use CRISPR-Cas9 for targeting an ERK docking site of Drosophila Cic, thus generating ERK-insensitive mutants of this important signaling sensor.