(A) Q-PCR on antral gastric cDNA prepared from untreated gp130^Y757F/Y757F mice, as well as gp130^+/+ mice either untreated or injected with a single dose of recombinant IL-11 or IFN-α. Expression data following normalization for 18S expression are shown and are presented from replicate analysis as the mean fold induction ± SD relative to expression in gp130^+/+ samples. n = 3 mice per genotype and treatment. *P < 0.05 versus expression in untreated gp130^+/+ samples. (B) Immunoblot analysis of total STAT3 and tyrosine-phosphorylated STAT3 in antral gastric tissue lysates from mice shown in A. (C) Transcriptional activation of the mouse Il11 gene in wild-type MEFs following transient transfection of the pIL11-luc firefly luciferase reporter construct. Triplicate cultures of cells, cotransfected with pTK-RL, were stimulated with the indicated amount of recombinant IFN-α, IFN-γ, or ^HYPERIL-6. Luciferase activity was determined 48 hours later and normalized against activity of the Renilla luciferase reporter and expressed relative to unstimulated control cultures. pAPRE-luc and pISRE-luc transfectants were used to assess for specific STAT3- and STAT1-mediated reporter activation. Data are representative of replicate analyses and are expressed as means of fold changes relative to unstimulated controls ± SD. *P < 0.05 versus expression in unstimulated cultures. (D) Schematic representation of pIL11-luc reporter plasmid depicting positions of potential STAT3 (top) and STAT1 (bottom) binding sites relative to the 5′ end of exon 1 of the mouse Il11 gene. The palindromic core motifs of the STAT binding sites are indicated in upper-case letters, and spacer sequences are indicated in lower-case letters.