GSE167470
Transgenic mice for in vivo epigenome editing with CRISPR-based systems [foxp3_p300 ChIP-seq]
The discovery, characterization, and adaptation of the RNA-guided clustered regularly interspersed short palindromic repeat (CRISPR)-Cas9 system has greatly increased the ease with which genome and epigenome editing can be performed. Fusion of chromatin-modifying domains to the nuclease-deactivated form of Cas9 (dCas9) has enabled targeted gene activation or repression in both cultured cells and in vivo in animal models. However, delivery of the large dCas9 fusion proteins to target cell types and tissues is an obstacle to widespread adoption of these tools for in vivo studies. Here we describe the generation and validation of two transgenic mouse lines for targeted gene regulation, including Rosa26:LSL-dCas9-p300 for gene activation and Rosa26:LSL-dCas9-KRAB for gene repression. Using the dCas9p300 and dCas9KRAB transgenic mice we demonstrate activation or repression of genes in both the brain and liver in vivo, and T cells ex vivo. We show gene regulation with gRNAs targeting either transcriptional start sites (TSS) or distal enhancer elements, as well as corresponding changes to downstream phenotypes. These mouse lines are convenient and valuable tools for facile, temporally controlled, and tissue-restricted epigenome editing and manipulation of gene expression in vivo. Overall design: Th0 cells from Rosa26-LSL-dCas9p300-Cd4Cre mice (with or without Cd4-Cre) were treated with retrovirus expressing gRNA (control or Foxp3 targeting) in vitro. Transduced cells were harvest three days after treatment