Fig. 5.

Conversion of TERT promoter mutation to WT promoter abolishes the regulation of the RAS-ERK pathway on TERT reactivation. ChIP was performed in control or trametinib-treated BLM mutant TERT (−146C > T) promoter CRISPR cells (A) or BLM WT TERT promoter CRISPR cells (B) using antibodies specific for RNA polymerase II (Pol II), H3K4me3, and H3K9ac and IgG as negative control. Enrichment of TERT promoter DNA fragments in ChIP DNA was normalized to DNA input. (C) ERK2 is bound to mutant TERT promoters of BRAF/NRAS-mutant melanoma cells. ChIP was performed in si-Ctrl or si-BRAF–treated A375, WM793, and Malme-3M cells and control or trametinib-treated BLM cells using ERK-2–specific antibody and IgG as negative control. Data shown represent two independent experiments for all cell lines. *P < 0.05, Student’s t test (two-tailed).