Figure 2. Detection of B2m-TALEN-mediated modifications of B2m in founder pigs.

(a) A representative photo showing 52-day-old founder pigs carrying B2m mutations. (b) PCR products of the targeted region of B2m from founder pigs co-microinjected with a pair of TALEN mRNA. Eight piglets were born and one died soon after birth. The seven alive founders were named from T1 to T7. Con denotes wild-type pig as control. (c) Detection of TALEN-mediated on-target cleavage of B2m by T7EN1 cleavage assays. All PCR products from (b) were subjected to T7EN1 cleavage assays. All the founders except T7 could be digested by T7EN1 which suggests that these founders carry B2m mutations. (d) Sequencing results of modified B2m alleles detected in founder pigs. At least 16 TA clones of the PCR products were analyzed. Sequences targeted by left and right TALEN are labeled in red and green respectively. The mutations in blue, lower case; deletions (−), N/N indicates positive colonies out of total sequenced. See also Figure S1. (e) Summary of generated B2m mutant pigs by TALENs. Founders showed more than two genotypes are considered as mosaicism.