Figure 3

Methylation status of individual CpG sites on upper and lower strands at IL-8 promoter. (A) Schematic representation of human IL-8 gene promoter. Regulatory upstream region (proximal NF-κB binding site and TATA box), Transcriptional start site (arrow) and exon 1 (gray box) are indicated. The relative positions of each CpG site present in the analyzed region and of the primers utilized for amplification are indicated. (B) Methylation degree at CpG sites -83, -7, +73, +119, and +191 on both upper (gray bars) and lower strand (black bars) was measured in untreated HT-29, in cells treated 24 hours with LPS and in normal colon mucosa samples by MALDI-TOF analysis. Methylation of sites -83 and -73 on lower strand could not be determined by MALDI analysis (ND). Each experiment was repeated three times on three different samples. Shown are the average values for each indicated CpG site ± SD.