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. Author manuscript; available in PMC: 2021 Mar 31.
Published in final edited form as: FASEB J. 2020 Aug 11;34(10):13533–13547. doi: 10.1096/fj.201903292RR

Figure 3. Chop is critical for the induction of E4bp4 by tunicamycin in PMHs and the mouse liver.

Figure 3.

(A) PMHs were transduced with AdshlacZ or Ad-shChop before treatment of tunicamycin for 24 hr. The cells were then harvested for mRNA analysis of E4bp4, Chop, and Grp78. (B-C) WT mice were tail-vein injected with either AdshLacZ or AdshChop for 10 days before intra-peritoneal injection of DMSO or tunicamycin for 24 hrs. The mRNA and protein levels of E4BP4 were analyzed by TR-qPCR and immunoblotting, respectively. (C) Activation of the E4bp4 promoter activity by ectopic expression of Chop. 293AD cells were transfected with a luciferase reporter construct driven by the E4bp4-WT promoter plus an increasing amount of the HA-Chop expression construct. The luciferase activity was normalized by the β-gal activity. (D) The E-box element in the promoter is required for its induction by CHOP. 293AD cells were transfected with the E4bp4-WT-luc or the E4bp4-ΔE-box-luc mutant plus the HA-Chop expression construct. The luciferase activity was normalized by the β-gal activity. Data were presented as Mean ± SD. *p <0.05, ***p <0.001 by unpaired Student t-test. The in vitro experiments were repeated at least twice with similar results.