Figure 1.

Methylation Profiles in the FMR1 Promoter and 5′-Upstream Segment in the Human Cell Line HCT116 and in Primary Human Fibroblasts

(A) Ideogram of the human X chromosome.

(B) Partial map shows the first ten exons (vertical bars) and introns of the FMR1 gene plus the upstream genome segment including the CGG repeat.

(C) Map of the 5′-upstream region of the FMR1 gene. The graph presents all CpG dinucleotides (1 to 104) in the region: The arrow indicates the start site of transcription. The promoter and an origin of DNA replication are also indicated. Nucleotide numbering in this and the following graphs was adapted from the NCBI nucleotide nomenclature: NC_000023:146,786,201–146,840,303 H. sapiens FMR1 gene region (nucleotide numbers on the human X = 23^rd chromosome). The boundary between unmethylated and methylated CpG dinucleotides is marked by the symbols ○ and ●, respectively, and is designated by a red bar.

(D) In HCT116 DNA, both strands (upper and lower panels) were sequenced with bisulfite between CpG pairs 20 and 83. Bisulfite sequencing in one strand was extended to CpG pair 104 (lower panel). □, unmethylated CpGs; ■, methylated CpGs.

(E) In primary human foreskin fibroblasts, DNA was sequenced with bisulfite between CpG pairs 20 and 104.