Bacterial type III secretion system-mediated injection of TALEN proteins into mouse embryonic stem cells. (A): Scheme of TALEN binding sites on gfp gene. The left and right TALEN-binding sequences are shown in green and blue, respectively, and the spacer sequence is shown in red. (B): GFP-expressing B5 mouse embryonic stem cell line (EB5) cells were infected with the indicated strains at a multiplicity of infection (MOI) of 100 for 3 hours. For ΔSTY/TALEN1&2, the total MOI was 200. Nuclear proteins were extracted and subjected to Western blot by an anti-FLAG antibody. (C): EB5 cells were infected with PAK-JΔSTY/pExoS54-FLAG-TALEN-1 and PAK-JΔSTY/pExoS54-FLAG-TALEN-2 at an overall MOI of 200 for 3 hours. After termination of the bacterial infection (time 0 hour), nuclear proteins were extracted at the indicated time and subjected to Western blot by anti-FLAG antibody. Abbreviations: ExoS54, exotoxin S N-terminal 54 amino acids; GFP, green fluorescent protein; h, hour; TALEN, transcription activator-like effector nuclease; TALEN1&2, PAK-JΔSTY/pExoS54-FLAG-TALEN1 and PAK-JΔSTY/pExoS54-FLAG-TALEN2.