TY - JOUR T1 - Cell-specific CRISPR/Cas9 activation by microRNA-dependent expression of anti-CRISPR proteins JF - bioRxiv DO - 10.1101/480384 SP - 480384 AU - Mareike D. Hoffmann AU - Sabine Aschenbrenner AU - Stefanie Grosse AU - Kleopatra Rapti AU - Claire Domenger AU - Julia Fakhiri AU - Manuel Mastel AU - Roland Eils AU - Dirk Grimm AU - Dominik Niopek Y1 - 2018/01/01 UR - http://biorxiv.org/content/early/2018/11/27/480384.abstract N2 - The rapid development of CRISPR/Cas technologies brought a personalized and targeted treatment of genetic disorders into closer reach. To render CRISPR-based therapies precise and safe, strategies to confine the activity of Cas(9) to selected cells and tissues are highly desired. Here, we developed a cell type-specific Cas-ON switch based on miRNA-regulated expression of anti-CRISPR (Acr) proteins. We inserted target sites for miR-122 or miR-1, which are abundant specifically in liver and muscle cells, respectively, into the 3’UTR of Acr transgenes. Co-expressing these with Cas9 and sgRNAs resulted in Acr knockdown and correspondingly in Cas9 activation solely in hepatocytes or myocytes, while Cas9 was efficiently inhibited in off-target cells. We demonstrate control of genome editing and gene activation using a miR-dependent AcrIIA4 in combination with different Streptococcus pyogenes (Spy)Cas9 variants (full-length Cas9, split-Cas9, dCas9-VP64). Finally, to showcase its modularity, we adapted our Cas-ON system to the smaller and more target-specific Neisseria meningitidis (Nme)Cas9 orthologue and its cognate inhibitors AcrIIC1 and AcrIIC3. Our Cas-ON switch should facilitate cell-specific activation of any CRISPR/Cas orthologue, for which a potent anti-CRISPR protein is known. ER -