Methylation status of each of the 19 CpG dinucleotides in amplicon 1. Each CpG dinucleotide within the amplicon is represented by a column and its position in base pairs relative to the CpG island is given at the top of the figure. Positions were measured from the end of the CpG nearest the 5' end of CSMD1 as defined by data obtained from the UC Santa Cruz genome browser (island sequence beginning CGGTGTGCGGCGTGAGCTTCCCCCACCCGAG...). Each sequenced clone is represented by a row and is numbered sequentially starting from the top of the figure. Open symbols (○) indicate that cytosine residue of the dinucleotide was unmethylated, closed symbols (●) indicate that it was methylated, and "x" indicates that the identity of the base could not be determined from that sequencing reaction. The level of expression is presented as a percentage relative to five pooled samples of normal UPPP epithelium. These are not the same UPPP samples used for measurement of promoter methylation in normal tissue. A) normal oropharyngeal epithelium from five individuals undergoing uvulopalatopharyngoplasty. B) Methylation status of two cell lines that express large CSMD1 transcripts from the normal promoter (PCI-13 and UPCI:SCC066), C) cell lines with low expression of the CSMD1 transcript from the normal promoter (PCI-2, PCI-1, PCI-100, 094, 041, UPCI:SCC056, and UPCI:SCC104).