Figure 5.

XBP-1 induction in the acute phase response. (A) Gene induction after partial hepatectomy. Total cellular RNA collected in a time course after partial hepatectomy in +/+ mice was probed sequentially with the cDNAs for XBP-1, C/EBPβ, and control β2 microglobulin. (B) Northern blot of mRNA prepared from +/+ (E12.5 or E13.5) or −/− (E13.5) fetal livers, or from the embryo torsos with the livers removed (body). The blot was sequentially hybridized with probes for α₁AT, αFP, transthyretin, apoA-1, vitamin D binding protein (VDBP), C-reactive protein (CRP), serum amyloid P (SAP), and γ-actin. (C) Transfections of an α₁AT reporter construct or an α₁AT reporter containing a mutation of the −1100-bp presumptive XBP-1 binding site (mut α₁AT; the ACGT core changed to GTAG) (Clauss et al. 1996), along with an XBP-1 expression plasmid (XBP) or a frameshifted mutant XBP-1 plasmid (XBP-Δ) (Reimold et al. 1996b).