FIG 4.

CHIP assay showing binding of XBP-1s to the vIL-6 promoter. BCBL-1 endogenous XBP-1s was induced by TM treatment (2 μg/ml) for 48 h and then cross-linked. Chromatin IP of fragmented DNA was performed with XBP-1 antibody or control IgG. Precipitated DNA was assayed by qPCR with specific primers for amplification of XRE2 or XRE3 of the vIL-6 promoter, and the data were quantitated as described in Materials and Methods. Results shown are the means ± standard deviations of triplicate determinations from a typical experiment of two experiments performed. In controls performed at the same time, DNA immunoprecipitated with histone H3 antibody, but not with XBP-1 antibody or a control IgG, was enriched for RPL30 exon 3.