VP64 and VP160 sequences containing 4 or 10 copies of the nucleotides encoding VP16 minimal transactivator sequence DALDDFDLDML18 (link) (Table S3) were synthesized (GenScript) and subcloned in the N-terminus of dCas9 in the pCI-neo vector (Promega). The dCas9. VP64-p65-Rta (VPR) construct19 (link) which served as the template for the various PCR amplifications was purchased from Addgene (#63,798; Cambridge, MA, USA). All VP-based constructs were subcloned into the pCI/neo expression vector (Promega) for uniformity. The Cas-effector with synthetic activation motif (SAM) targeting the mouse TIMP1 gene was purchased from Santa Cruz Biotechnology (sc-423402-ACT, Santa Cruz, CA, USA).