FIG. 3.
Induction of UPR target genes by XBP-1s. MEF-tet-off and MEF-tet-off-XBP-1s cells were cultured in medium containing 1 μg of doxycycline/ml. XBP-1s expression was induced by culturing the cells for 3 days in doxycycline-free medium or by treatment with Tm for the indicated times. XBP-1s protein was revealed by anti-XBP-1 antibody in Western blot analyses. Total RNA was also prepared to measure the expression level of BiP, CHOP, ERdj4, p58IPK, and ATF6α mRNA. (B) Additional XBP-1-dependent target genes identified in gene profiling experiments (Table 2) were confirmed by Northern analysis. Ethidium bromide staining of the gels before blotting is shown at the bottom.