Figure 5

Methylation status of CpG sites in the NORE1A promoter. A map of the CpG sites within the proximal region of the NORE1A promoter (A). CpGs sites are represented by vertical lines. The transcription start site is indicated by an arrow at +1. Nucleotide sequences of NORE1A promoter region examined by bisulfite DNA sequencing analysis (B). Thirty one CpG sites (bold) examined are numbered 1-31 and primers for PCR were indicated. The ATG start codon is indicated (boxed). Methylation status of 31 CpG sites in the NORE1A promoter and its association with mRNA level in colorectal cancer cell lines (C). The promoter region comprised of 31 CpGs was amplified by PCR. The PCR products were cloned and 5 plasmid clones were sequenced for each cell line. Percent methylation was determined by the number of alleles containing a methylated CpG at each position. Black, gray, and white squares represent complete methylation (4-5 clones), partial methylation (1-3 clones), and unmethylation (0 clone), respectively. Comparison of CpG sites methylation between primary tumors and adjacent noncancerous tissues (D). N, noncancerous tissue; T, tumor tissue; P, patient.