Fig. 1

Expression of RAI2 is inactivated by DNA methylation in colorectal cancer cell lines. a Schematic diagram of CpG islands in the RAI2 promoter region. MF, MSP forward primer; MR, MSP reverse primer; UF, unmethylation forward primer; UR, unmethylation reverse primer; BSSQ-F, bisulfite sequencing forward primer; BSSQ-R, bisulfite sequencing reverse primer. b Expression of RAI2 was analyzed by semi-quantitative RT-PCR and Western blot in colorectal cancer cell lines (DKO, HCT116, RKO, HT29, SW480, SW620, LOVO, and DLD1). c Methylation status of RAI2 detected by MSP in colorectal cancer cell lines. IVD, in vitro-methylated DNA; NL, normal lymphocyte DNA; M, methylated alleles; U, unmethylated alleles. d Expression of RAI2 was analyzed by RT-PCR in colorectal cancer cell lines in the absence or presence of 2 μmol/l DAC (+) for 96 h. e Bisulfite sequencing of RAI2 was performed in SW620, HT29, and LOVO cell lines. The region of CpG islands studied by MSP is indicated by a double-headed arrow spanning 95 bp. Filled circles represent methylated CpG sites within the RAI2 CpG islands, and open circles denote unmethylated CpG sites. Bisulfite sequencing focused on a 212-bp (+ 902 to + 1113 bp) CpG islands downstream of the RAI2 transcription start site