Generation of mutant mice using the CRISPR/Cas9 system
Thanks to the identification of the CRISPR/Cas9 system meanwhile it is possible to generate new mouse models by microinjection of Cas9 mRNA together with one or multiple guide RNAs into the pronucleus of mouse zygotes. This method provides several advantages, on the one hand a reduction of breedings and animals needed, on the other hand the possibility to induce even multiple mutations in one step and directly in the background strain of choice.
Generation of mutant mice using the PiggyBAC transgenesis technique
Bacterial artificial chromosomes (BACs) allow the transgenesis of large genomic DNA fragments but only at moderate efficiency. The system can be considerably enhanced by inserting piggyBAC transposon elements into the BAC vector. Subsequent microinjection of the piggyBAC vector together with PB transposase mRNA into the pronucleus of mouse zygotes efficiently integrates the gene-of-interest into the genomic DNA.