Efficient Production of Gene-Modified Mice using Staphylococcus aureus Cas9

Sci Rep. 2016 Sep 2:6:32565. doi: 10.1038/srep32565.

Abstract

The CRISPR/Cas system is an efficient genome-editing tool to modify genes in mouse zygotes. However, only the Streptococcus pyogenes Cas9 (SpCas9) has been systematically tested for generating gene-modified mice. The protospacer adjacent motif (PAM, 5'-NGG-3') recognized by SpCas9 limits the number of potential target sites for this system. Staphylococcus aureus Cas9 (SaCas9), with its smaller size and unique PAM (5'-NNGRRT-3') preferences, presents an alternative for genome editing in zygotes. Here, we showed that SaCas9 could efficiently and specifically edit the X-linked gene Slx2 and the autosomal gene Zp1 in mouse zygotes. SaCas9-mediated disruption of the tyrosinase (Tyr) gene led to C57BL/6J mice with mosaic coat color. Furthermore, multiplex targeting proved efficient multiple genes disruption when we co-injected gRNAs targeting Slx2, Zp1, and Tyr together with SaCas9 mRNA. We were also able to insert a Flag tag at the C-terminus of histone H1c, when a Flag-encoding single-stranded DNA oligo was co-introduced into mouse zygotes with SaCas9 mRNA and the gRNA. These results indicate that SaCas9 can specifically cleave the target gene locus, leading to successful gene knock-out and precise knock-in in mouse zygotes, and highlight the potential of using SaCas9 for genome editing in preimplantation embryos and producing gene-modified animal models.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Base Sequence
  • CRISPR-Cas Systems / genetics*
  • DNA Repair
  • Embryo, Mammalian / metabolism
  • Founder Effect
  • Gene Knock-In Techniques
  • Gene Targeting
  • Genetic Engineering / methods*
  • Mice, Inbred C57BL
  • Mice, Mutant Strains
  • Mice, Transgenic
  • Mosaicism
  • RNA, Guide, CRISPR-Cas Systems / genetics
  • Staphylococcus aureus / genetics*

Substances

  • RNA, Guide, CRISPR-Cas Systems