Break-induced telomere synthesis underlies alternative telomere maintenance

Article

关键词: DNA-POLYMERASE-DELTA;    INDUCED REPLICATION;    HUMAN-CELLS;    ACCESSORY SUBUNITS;    REPAIR;    YEAST;    RECOMBINATION;    PATHWAY;    ABSENCE;    PCNA;   

DOI  :  10.1038/nature20099

来源: SCIE

【 摘 要 】

Homology-directed DNA repair is essential for genome maintenance through templated DNA synthesis. Alternative lengthening of telomeres (ALT) necessitates homology-directed DNA repair to maintain telomeres in about 10-15% of human cancers. How DNA damage induces assembly and execution of a DNA replication complex (break-induced replisome) at telomeres or elsewhere in the mammalian genome is poorly understood. Here we define break-induced telomere synthesis and demonstrate that it utilizes a specialized replisome, which underlies ALT telomere maintenance. DNA double-strand breaks enact nascent telomere synthesis by long-tract unidirectional replication. Proliferating cell nuclear antigen (PCNA) loading by replication factor C (RFC) acts as the initial sensor of telomere damage to establish predominance of DNA polymerase delta (Pol delta) through its POLD3 subunit. Break-induced telomere synthesis requires the RFC-PCNA-Pol delta axis, but is independent of other canonical replisome components, ATM and ATR, or the homologous recombination protein Rad51. Thus, the inception of telomere damage recognition by the break-induced replisome orchestrates homology-directed telomere maintenance.

【 授权许可】

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