Boon Haow Chua1,2, Nurkaiyisah Zaal Anuar1, Laure Ferry3, Cecilia Domrane3, Anna Wittek1, Vineeth T. Mukundan1, Sudhakar Jha1,2,4,5, Falk Butter6,7, Daniel G. Tenen1,8, Pierre-Antoine Defossez3 and Dennis Kappei1,2,4 1Cancer Science Institute of Singapore, National University of Singapore, 117599 Singapore; 2Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 117596 Singapore; 3Université Paris Cité, CNRS, Epigenetics and Cell Fate, F-75013 Paris, France; 4NUS Center for Cancer Research, Yong Loo Lin School of Medicine, National University of Singapore, 117599 Singapore; 5Department of Physiological Sciences, College of Veterinary Medicine, Oklahoma State University, Stillwater, Oklahoma 74078, USA; 6Institute of Molecular Biology (IMB), 55128 Mainz, Germany; 7Institute of Molecular Virology and Cell Biology (IMVZ), Friedrich Loeffler Institute, 17493 Greifswald, Germany; 8Harvard Stem Cell Institute, Harvard Medical School, Boston, Massachusetts 02115, USA Corresponding author: dennis.kappeinus.edu.sg Abstract

Point mutations within the TERT promoter are the most recurrent somatic noncoding mutations identified across different cancer types, including glioblastoma, melanoma, hepatocellular carcinoma, and bladder cancer. They are most abundant at −146C > T and −124C > T, and rarer at −57A > C, with the latter originally described as a familial case, but subsequently shown also to occur somatically. All three mutations create de novo E26-specific (ETS) binding sites and result in activation of the TERT gene, allowing cancer cells to achieve replicative immortality. Here, we used a systematic proteomics screen to identify transcription factors preferentially binding to the −146C > T, −124C > T, and −57A > C mutations. Although we confirmed binding of multiple ETS factors to the mutant −146C > T and −124C > T sequences, we identified E4F1 as a −57A > C–specific binder and ZNF148 as a TERT wild-type (WT) promoter binder that showed reduced interaction with the −124C > T allele. Both proteins are activating transcription factors that bind specifically to the −57A > C and WT (at position 124) TERT promoter sequence in corresponding cell lines, and up-regulate TERT transcription and telomerase activity. Our work describes new regulators of TERT gene expression with possible roles in cancer.

Footnotes

[Supplemental material is available for this article.]

Article published online before print. Article, supplemental material, and publication date are at https://www.genome.org/cgi/doi/10.1101/gr.277724.123.

Freely available online through the Genome Research Open Access option.

Received January 20, 2023. Accepted October 23, 2023.