Chopper Is Prodeath Regardless of the Effect of p75ICD on Sensitivity to Oxidative Stress

Figure 1

Regulating p75ICD expression using the pBIG2i Tet-inducible expression system. Full-length p75ICD (ICD-A) or the N-terminal deletion mutant (ICD-B) was expressed from the bidirectional tetracycline regulated vector pBIG2i. In the presence of ligand (doxycycline), the reverse transactivator (rtTA) expressed from the thymidine kinase promoter (TK) binds to the heptemerized tetO sequence activating transgene expression from both the minimal TK and CMV promoters. Inclusion of the IRES-eGFP cassette facilitates the analysis of p75ICD expressing clones. Domains included in the full-length ICD include the amino terminal “chopper domain”, tandem PEST sequence, Traf2- and PDZ-binding domains, and the carboxyl terminal death domain. In addition to using IRES-mediated GFP expression, both ICD expression constructs contain the V5 epitope to monitor inducible ICD transgene expression.