MLH1 promoter germline-methylation in selected probands of Chinese hereditary non-polyposis colorectal cancer families

Figure 1 Results of MLH1 MSP assay using primers that amplify methylated (M) or unmethylated (U) alleles (Lane M represents 100-bp DNA marker). A: MLH1 MSP assay in families H10, H65 and cell line SW48. M1, M2, U1and U2 indicate the methylated and unmethylated products of familiy H10, cell line SW48, and the methylaed band (115 bp); M3 and U3 indicate the methylated and unmethylated products in family H65; B: MLH1 MSP assay in families H7, H12, H30, H10, H29, H41, H65 and cell line SW48. U7, U12, U30, U41 and U65 indicate the unmethylated products of families H7, H12, H30, H41, and H65,respectively; M10, M29 and MSW indicate the methylated products of families H10, H29, and positive control SW48, respectively; C: MLH1 MSP assay in families H8, H32, H10, H60, H29, H42 H65 and cell line SW48. U8, U60 and U65 indicate the unmethylated products of families H8, H60 and H6, respectively; M10, M29 and MSW indicate the methylated products of families H10, H29, and positive control SW48, respectively; U32, M32 and U42, M42 are products of families H32 and H42, respectively.

Figure 2 Methylation analysis of the promoter MLH1 gene by clone sequencing. Arrow indicates CpG dinucleotide, WTS indicates the wild-type sequence of transcription start site. A: Unmethylated band presenting all unmethylated cytosines was converted to uracil after bisulfite modification; B: Methylated band presenting all unmethylated cytosines was unchanged after bisulfite modification.