biostudies-literatureUnknown13(1)Romero-Zamora DJapan Foundation for Applied EnzymologyTelomeric ends form a loop structure (T-loop) necessary for the repression of ATM kinase activation throughout the normal cell cycle. However, cells undergoing a prolonged mitotic arrest are prone to lose the T-loop, resulting in Aurora B kinase-dependent mitotic telomere deprotection, which was proposed as an anti-tumor mechanism that eliminates precancerous cells from the population. The mechanism of mitotic telomere deprotection has not been elucidated. Here, we show that WRN, a RECQ helicase family member, can suppress mitotic telomere deprotection independently of its exonuclease and helicase activities. Truncation of WRN revealed that N-terminus amino acids 168-333, a region that contains a coiled-coil motif, is sufficient to suppress mitotic telomere deprotection without affecting bScientific reports645https://www.ebi.ac.uk/biostudies/studies/S-EPMC9837040biostudies-literatureA non-catalytic N-terminus domain of WRN prevents mitotic telomere deprotection.PMC9837040Hayashi MTRomero-Zamora DfalseA non-catalytic N-terminus domain of WRN prevents mitotic telomere deprotection.Telomeric ends form a loop structure (T-loop) necessary for the repression of ATM kinase activation throughout the normal cell cycle. However, cells undergoing a prolonged mitotic arrest are prone to lose the T-loop, resulting in Aurora B kinase-dependent mitotic telomere deprotection, which was proposed as an anti-tumor mechanism that eliminates precancerous cells from the population. The mechanism of mitotic telomere deprotection has not been elucidated. Here, we show that WRN, a RECQ helicase family member, can suppress mitotic telomere deprotection independently of its exonuclease and helicase activities. Truncation of WRN revealed that N-terminus amino acids 168-333, a region that contains a coiled-coil motif, is sufficient to suppress mitotic telomere deprotection without affecting b2023-01-01T00:00:00Z2023 Jan2025-04-04T13:53:37.898Z2025-04-04T13:53:37.898ZS-EPMC98370403663530710.1038/s41598-023-27598-0