Epigenetic regulation of Claudin 11 (CLDN11) in malignant melanoma. (a) Structure of the CLDN11 CpG island promoter on chromosome 3 and the CLDN11 protein (207 aa). Arrows mark transcriptional (+1) start site for CLDN11. Vertical lines indicate CpGs. The 157 bp PCR product with respective primers and the TaqI site are depicted. The conserved Claudin_2 superfamily domain of CLDN11 is marked; (b) Methylation analysis of CLDN11 by COBRA. Bisulfite-treated DNA from MM cell lines (buf1280, C8161, IGR1, MeWo, SKMEL13 and SKMEL28), lung cancer A549, HeLa and human fibroblasts (HF) was amplified, digested with TaqI (+) or mock digested (−) and resolved on 2% gels with a 100 bp marker (M). The methylation status of CLDN11 (meth./methylated and unmeth./unmethylated) and BRAF status (WT/wild type, V600E/Codon 600 mutation and nd/not determined) are indicated.