Figure 3.

 Chromatin immunoprecipitation assay of p65 binding to a nuclear factor κB (NFκB) regulatory region within the inducible nitric oxide synthase (iNOS) promoter in nuclear extracts of colonic mucosal biopsies from patients with uninflamed bowel (C; n = 2), collagenous colitis (COC, n = 2), or active ulcerative colitis (UC, n = 2). Soluble chromatin was prepared from formaldehyde cross linked sonicated biopsies. Specific antibody against p65 was used to precipitate protein bound DNA fragments which were subsequently amplified by polymerase chain reaction using primers flanking an NFκB regulatory region (−5979 to −5779; primer pair A) or a non-regulatory region (−2741 to −2534; primer pair B). Total input refers to amplification of 1% of the total amount of DNA prior to immunoprecipitation.