Comparison of TALEs with different activation domain in HUDEP-2 cells. (A) TALE vector design. The EF1 short promoter was used to drive the TALE expression. The TALEs were fused with a Ldb1 or Ldb2 dimerization domain, followed by a T2A GFP cassette. The activation domain of VP64 was inserted before the Ldb1/2 dimerization domain to test whether the gene activation could be bolstered. To prevent deletions caused by repeats of TALEs during the lentivirus packing process, we changed the TALE’s DNA codons by using codon-optimized DNA for their expression. (B) HUDEP-2 cells were infected with TALE-expressing lentivirus. RNA was prepared after 7 days. qRT-PCR was performed using HBG as probe, normalized by HBA amount. (C) Relative β-globin mRNA level by qRT-PCR, using HBB as probe, normalized by HBA amount. The vector copy number (VCN) was determined and depicted in the graph. The statistical significance was calculated by 1-way ANOVA followed by Dunnett’s multiple comparisons test. ****P < .0001. Values mean ± SEM. (D) Bar graphs show proportions of the fetal-globin protein relative to total globin amount level determined by HPLC. Analyses are also indicated with their relevant VCN.