Telomere recombination requires the MUS81 endonuclease.
Telomerase-negative cancer cells maintain their telomeres through the alternative lengthening of telomeres (ALT) pathway. Although a growing body of evidence demonstrates that the ALT mechanism is a post-replicative telomere recombination process, molecular details of this pathway are largely unknown. Here we demonstrate that MUS81, a DNA structure specific recombination endonuclease, has a key role in the maintenance of telomeres in human ALT cells. We find that MUS81 specifically localizes to ALT-associated promyelocytic leukaemia (PML) nuclear bodies (APBs) and associates with telomeric DNA in ALT cells, which is enriched during the G2 phase of the cell cycle. Depletion of MUS81 results in the reduction of ALT-specific telomere recombination and leads to proliferation arrest of ALT cells. In addition, the endonuclease activity of MUS81 is required for recombination-based ALT cell survival, and the interaction of MUS81 with the telomeric repeat-binding factor TRF2 regulates this enzymatic activity, thereby maintaining telomere recombination. Thus, our results suggest that MUS81 is involved in the maintenance of ALT cell survival at least in part by homologous recombination of telomeres.
Department of Radiation Oncology, Washington University School of Medicine, 4511 Forest Park, St. Louis, MO 63108, USA.
Sicong
S
Zeng
Tao
T
Xiang
Tej K
TK
Pandita
Ignacio
I
Gonzalez-Suarez
Susana
S
Gonzalo
Curtis C
CC
Harris
Qin
Q
Yang
D000818:Animals; D055162:Biocatalysis; D002453:Cell Cycle / Q000502:physiology; D045744:Cell Line, Tumor; D002466:Cell Nucleolus / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D049109:Cell Proliferation; D002470:Cell Survival / Q000502:physiology; D047369:Chromatin Immunoprecipitation; D004268:DNA-Binding Proteins / Q000502:physiology*; D004706:Endodeoxyribonucleases / Q000378:metabolism; D004720:Endonucleases / Q000502:physiology*; D016195:G2 Phase / Q000502:physiology; D006801:Humans; D051379:Mice; D011485:Protein Binding / Q000187:drug effects / Q000502:physiology; D034622:RNA Interference; D011995:Recombination, Genetic / Q000502:physiology*; D012854:Sister Chromatid Exchange / Q000502:physiology; D019098:Telomerase / Q000235:genetics; D016615:Telomere / Q000235:genetics* / Q000378:metabolism; D035341:Telomeric Repeat Binding Protein 2 / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology
D004268:DNA-Binding Proteins; C504753:TERF2 protein, human; D035341:Telomeric Repeat Binding Protein 2; D019098:Telomerase; C507947:Eme1 protein, human; D004706:Endodeoxyribonucleases; D004720:Endonucleases; C498772:MUS81 protein, human