Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)The mechanism of telomerase re-activation in cancer had remained elusive until the discovery of frequent mutations in the promoter of the TERT gene that encodes the catalytic reverse transcriptase subunit of telomerase. We investigated the regulation of TERT expression in melanoma cell lines and our results show that promoter mutations render TERT expression dependent on MAPK activation due to oncogenic BRAF or NRAS mutations. Mutations in the TERT promoter create binding sites for ETS transcription factors. ETS1, expressed in melanoma cell lines, undergoes activating phosphorylation by ERK at Thr38 residue as a consequence of constitutively activated MAPK pathway. We demonstrate that ETS1 binds on the mutated TERT promoter leading to the re-expression of the gene. The inhibition of ETS1 resulted in reduced TERT expression. We provide evidence that the TERT promoter mutations provide a direct link between TERT expression and MAPK pathway activation due to BRAF or NRAS mutations via the transcription factor ETS1.7335312753136CAPES - Brazilian Federal Agency for Support and Evaluation of Graduate Education within the Ministry of Education of BrazilLigue Contre le Cancer Comite de ParisGEFLUC Paris-Ile-de-FranceFondation ARC pour la Recherche sur le CancerINSERMUniversite Paris DiderotTRANSCAN through German Ministry of Education and Science [01KT1511]Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)