Fig. 1.

Design of guide RNA and homologous recombination ssODN for CRISPR/Cas9 gene editing of chicken ALV-J receptor chNHE1 in primordial germ cells. (A) The structure of coding exons and introns of chNHE1 (Top), the CRISPR/Cas9 target sequence of exon 1 with the guide RNA (gRNA) complementary sequence (underlined) and the TGG triplet encoding W38 (red on the yellow background; Middle), and the central part of the ssODN template for homologous recombination with deleted TGG triplet and a single nucleotide substitution (in red) creating the BsaI restriction site (Bottom). (B) Preparation of ΔW38 chickens: schematic representation of the workflow and timeline.