FIG. 1.

Structure of the XBP-1 gene and protein in wt and mutant cells. (A) XBP-1 locus in wt and XBP-1^−/− MEF cells. Splicing of the mutant XBP-1 mRNA in XBP-1^−/− cells is shown. Asterisks represent termination codons. (B) wt and XBP-1^−/− MEF cells were either not treated or treated with 10 μg of Tm/ml for 6 h. XBP-1 mRNA was revealed by Northern blot analysis. (C) wt and XBP-1^−/− MEF cells were treated with 10 μM MG-132 or 10 μg of Tm/ml for 6 h. XBP-1u and XBP-1s proteins were detected by Western blot analysis with anti-XBP-1 antibody.