Construction of a CRISPR-Cas9 System for Pig Genome Targeting.

ABSTRACT

A Cas9/sgRNA RNA-guided endonuclease expression system including a codon-optimized Streptococcus pyogenes A20 Cas9 recombinant protein expression vector and a spacer-guide chimeric RNA expression vector using the porcine U6 promoter was constructed for application in pigs. Only the Flag2-NLS1-Cas9-NLS2 recombinant protein in complex with sgRNA was translocated into the nucleus; the Flag2-NLS1-Cas9-NLS2 protein alone was excluded from the nucleus. Up to 13% of porcine PK1 cells targeted in vitro were observed, regardless of transfection efficiency.