A Mouse Model of X-Linked Chronic Granulomatous Disease for the Development of CRISPR/Cas9 Gene Therapy.

Chronic granulomatous disease (CGD) is an inherited immunodeficiency disease mainly caused by mutations in the X-linked gene that abrogate reactive oxygen species (ROS) production in phagocytes and microbial defense. Gene repair using the CRISPR/Cas9 system in hematopoietic stem and progenitor cells (HSPCs) is a promising technology for therapy for CGD. To support the establishment of efficient and safe gene therapies for CGD, we generated a mouse model harboring a patient-derived mutation in the gene.

Enhancement of CRISPR-Cas9 induced precise gene editing by targeting histone H2A-K15 ubiquitination.

Background: Precise genetic modifications are preferred products of CRISPR-Cas9 mediated gene editing in mammalian cells but require the repair of induced double-strand breaks (DSB) through homology directed repair (HDR). Since HDR competes with the prevailing non-homologous end joining (NHEJ) pathway and depends on the presence of repair templates its efficiency is often limited and demands optimized methodology.

Results: For the enhancement of HDR we redirect the DSB repair pathway choice by targeting the Ubiquitin mark for damaged chromatin at Histone H2A-K15.

Corrigendum: Enhancement of Precise Gene Editing by the Association of Cas9 With Homologous Recombination Factors.

[This corrects the article DOI: 10.3389/fgene.2019.

Enhancement of Precise Gene Editing by the Association of Cas9 With Homologous Recombination Factors.

The CRISPR-Cas9 system is used for genome editing in mammalian cells by introducing double-strand breaks (DSBs) which are predominantly repaired via non-homologous end joining (NHEJ) or to lesser extent by homology-directed repair (HDR). To enhance HDR for improving the introduction of precise genetic modifications, we tested fusion proteins of Cas9 nuclease with HDR effectors to enforce their localization at DSBs. Using a traffic-light DSB repair reporter (TLR) system for the quantitative detection of HDR and NHEJ events in human HEK cells we found that Cas9 fusions with CtIP, Rad52, and Mre11, but not Rad51C promote HDR up to twofold in human cells and significantly reduce NHEJ events.

Gene editing in mouse zygotes using the CRISPR/Cas9 system.

The generation of targeted mouse mutants is a key technology for biomedical research. Using the CRISPR/Cas9 system for induction of targeted double-strand breaks, gene editing can be performed in a single step directly in mouse zygotes. This article covers the design of knockout and knockin alleles, preparation of reagents, microinjection or electroporation of zygotes and the genotyping of pups derived from gene editing projects.