Figure 4: Development of aTALE transcriptional repressor architecture.

(a) Design of SOX2 TALE for TALE-repressor screening. A TALE targeting a 14-bp sequence within the SOX2 locus of the human genome was synthesized as described previously³. (b) List of all repressors screened and their host origin (left). Eight different candidate repressor domains were fused to the C-term of the SOX2 TALE. (c) The fold decrease of endogenous SOX2 messenger RNA (mRNA) is measured using qRT–PCR by dividing the SOX2 mRNA levels in mock-transfected cells by SOX2 mRNA levels in cells transfected with each candidate TALE repressor. (d) Transcriptional repression of endogenous CACNA1C. TALEs using NN, NK and NH as the G-targeting RVD were constructed to target a 18-bp target site within the human CACNA1C locus (site 1 in Fig. 3). Each TALE is fused to the SID repression domain. NLS, nuclear localization signal; KRAB, Krüppel-associated box. All results are collected from three independent experiments in HEK 293FT cells. Error bars indicate s.e.m.; n=3. *P<0.05, Student's t-test.