FIG. 6.

Methylation status of TFF1 to TFF3 in cultured colon cancer cells. (A) Schematic of the alignment of the three TFF genes on chromosome 21q22.3. The location of a separate gene, TMPRSS3, upstream from TFF1 is also shown. No CpG islands could be located anywhere along the depicted stretch of genomic sequence. (B) Methylation status of TFF1. A schematic of the 5′ region of the gene depicts the transcription start site (large vertical arrow) and exon 1 is shown in the rectangle, with the coding region portion shown in solid black. Vertical black triangles, GATA binding sites; vertical lines, CpG sites. Horizontal arrows (MSP) show the primer sites for the MSP analysis in the panel below for selected cancer cell lines and normal tissues (NC, normal colon; PBL, peripheral blood lymphocytes). (C) Schematic of the 5′ region of TFF2. All symbols are exactly as for those in Fig. 6A except that the horizontal arrow (BS) show the area represented in the bisulfite sequencing shown directly beside the schematic. For the sequencing all horizontal squares represent CpG sites in individual sequenced clones (white, unmethylated; black, methylated). The sequencing is shown for (i) HT29 cells in which the gene is expressed, (ii) HCT116 cells in which it is not, and (iii) these same cells which express the gene after adenoviral expression of GATA-5 (see Fig. 7). (D) Schematic of the 5′ region of TFF3. All symbols are as described for the other panels and, again, the horizontal arrow (BS) shows the area represented in the bisulfite sequencing shown directly beside the schematic.