Gene Targeting in Rabbits: Single-Step Generation of Knockout Rabbits by Microinjection of CRISPR/Cas9 Plasmids

The development of genome editing technology has allowed gene disruptions to be achieved in various animal species and has been beneficial to many mammals. Gene disruption using pluripotent stem cells is difficult to achieve in rabbits, but thanks to advances in genome editing technology, a number of gene disruptions have been conducted. This chapter describes a simple and easy method for carrying out gene disruptions in rabbits using CRISPR/Cas9 in which the gene to be disrupted is marked, the presence or absence of off-target candidates is checked, and a plasmid allowing simultaneous expression of Cas9 and sgRNA is constructed. Next, the cleaving activity of candidate sequences is investigated, and assessments are carried out to determine whether the target sequences can be cut. Female rabbits subjected to superovulation treatment are mated with male rabbits and fertilized eggs are collected, and then pronuclear injection of plasmid DNA is performed. The next day, the two-cell stage embryos are transplanted into a pseudopregnant rabbits, and offspring are born within approximately 29-30 days. The genomic DNA of the offspring is then examined to check what type of genetic modifications has occurred. With the advent of CRISPR/Cas9, the accessibility of gene disruptions in rabbits has improved remarkably. This chapter summarizes specifically how to carry out gene disruptions in rabbits.