Fig. 4

Genotyping and immunofluorescence of embryos generated by TALEN-mediated genome engineering. a Schematic overview of the strategy to generate an OCT4-EmGFP knock-in allele. The homologous arms of the donor vector are indicated as LA (839 bp) and RA (1001 bp). PCR primers used for PCR genotyping are shown as arrows in different colors. b PCR products obtained using primers L1-F and L1-R were sequenced. Sequence across the targeted region confirmed the correct fusion of EmGFP to the first exon of OCT4. c EmGFP: PCR genotyping using primers G-F and G-R produced bands of 421-bp fragment in the samples from nine embryos, suggesting the possible insertion or precise knock-in of the EmGFP gene. L1: PCR genotyping using primers L1-F and L1-R produced large products (3259 bp) in seven embryo samples, indicating the EmGFP sequence was integrated. The samples 0806.16C1, 0308 M4 and 0308.B1 only contain the larger product, suggesting either both alleles were targeted, or one allele failed to amplify. S1 and S2: PCR genotyping using primers S1-F and S1-R, S2-F and S2-R produced bands with correct size (1795 bp and 2109 bp) in the samples from the targeted embryos. d Immunostaining of targeted blastocysts using anti-GFP antibody showed a signal in the ICM. Scale bar, 50 μM