Fig. 1.
Design and characterization of the reversible CAR protein expression device induced by the genetic code expansion system. A Schematic representation of the genetic code expansion system, including tRNACUA, the orthogonal aminoacyl-tRNA synthetase (aaRS), and a dual fluorescent protein expression cassette. B&C EGFP protein expression in 293T cells incubated with different concentrations of BOCK, as detected by flow cytometry and fluorescence microscopy. D Schematic representation of the BiCAR expression system, in which TAG was inserted into the CAR coding region, individually located between the initiation codon and the CD19 ScFv (the front BiCAR, F-BiCAR), between the CD19 ScFv and the CD8 spacer (the middle BiCAR, M-BiCAR), and between the 4-1BB costimulatory domain and the CD3 zeta domain (the rear BiCAR, R-BiCAR). E&F Western blot analysis showed the expression level of the CAR protein in the three BiCAR systems induced by BOCK addition. The data are reported as the means ± SDs (n = 3). *p < 0.05, **p < 0.01, ***p < 0.001, not significant (ns) by t tests