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Mre11 and Blm-Dependent Formation of ALT-Like Telomeres in Ku-Deficient


The majority of cancer cells use a special enzyme called telomerase to maintain telomeres. However, some cancer cells do not possess telomerase and use instead the so-called ALT mechanism to maintain telomeres. ALT is a complex pathway that entails the action of many factors, and the telomere DNAs of ALT cancer cells are extremely abnormal (e.g., they are often detached from the rest of the chromosomes and often exist in single-stranded forms). Currently, there are few manipulations that one can use to induce normal cells to engage in the ALT mechanism. The lack of a good “model” system poses a major obstacle to the understanding of this pathway and the development of effective counter-measures against ALT cancer cells. By removing Ku and a checkpoint factor from U. maydis (a yeast-like fungus), we generated clones that exhibit many of the characteristic abnormalities of ALT cancer cells. Moreover, we identified two factors (i.e., Mre11 and Blm) that when deleted, abolished the ALT phenotypes. Further analysis of this model may lead to the development of new strategies for shrinking the telomeres of cancer cells, thereby arresting their proliferation.


Vyšlo v časopise: Mre11 and Blm-Dependent Formation of ALT-Like Telomeres in Ku-Deficient. PLoS Genet 11(10): e32767. doi:10.1371/journal.pgen.1005570
Kategorie: Research Article
prolekare.web.journal.doi_sk: https://doi.org/10.1371/journal.pgen.1005570

Souhrn

The majority of cancer cells use a special enzyme called telomerase to maintain telomeres. However, some cancer cells do not possess telomerase and use instead the so-called ALT mechanism to maintain telomeres. ALT is a complex pathway that entails the action of many factors, and the telomere DNAs of ALT cancer cells are extremely abnormal (e.g., they are often detached from the rest of the chromosomes and often exist in single-stranded forms). Currently, there are few manipulations that one can use to induce normal cells to engage in the ALT mechanism. The lack of a good “model” system poses a major obstacle to the understanding of this pathway and the development of effective counter-measures against ALT cancer cells. By removing Ku and a checkpoint factor from U. maydis (a yeast-like fungus), we generated clones that exhibit many of the characteristic abnormalities of ALT cancer cells. Moreover, we identified two factors (i.e., Mre11 and Blm) that when deleted, abolished the ALT phenotypes. Further analysis of this model may lead to the development of new strategies for shrinking the telomeres of cancer cells, thereby arresting their proliferation.


Zdroje

1. de Lange T (2009) How telomeres solve the end-protection problem. Science 326: 948–952. doi: 10.1126/science.1170633 19965504

2. Jain D, Cooper JP (2011) Telomeric strategies: means to an end. Annu Rev Genet 44: 243–269.

3. Harley C, Futcher A, Greider C (1990) Telomeres shorten during ageing of human fibroblasts. Nature 345: p458–460.

4. d'Adda di Fagagna F, Reaper PM, Clay-Farrace L, Fiegler H, Carr P, et al. (2003) A DNA damage checkpoint response in telomere-initiated senescence. Nature 426: 194–198. 14608368

5. Autexier C, Lue NF (2006) The Structure And Function of Telomerase Reverse Transcriptase. Annu Rev Biochem 75: 493–517. 16756500

6. Blackburn EH, Collins K (2011) Telomerase: an RNP enzyme synthesizes DNA. Cold Spring Harb Perspect Biol 3.

7. Buseman CM, Wright WE, Shay JW (2012) Is telomerase a viable target in cancer? Mutat Res 730: 90–97. doi: 10.1016/j.mrfmmm.2011.07.006 21802433

8. Cesare AJ, Reddel RR (2010) Alternative lengthening of telomeres: models, mechanisms and implications. Nat Rev Genet 11: 319–330. doi: 10.1038/nrg2763 20351727

9. Shay JW, Reddel RR, Wright WE (2012) Cancer. Cancer and telomeres—an ALTernative to telomerase. Science 336: 1388–1390. doi: 10.1126/science.1222394 22700908

10. Henson JD, Cao Y, Huschtscha LI, Chang AC, Au AY, et al. (2009) DNA C-circles are specific and quantifiable markers of alternative-lengthening-of-telomeres activity. Nat Biotechnol 27: 1181–1185. doi: 10.1038/nbt.1587 19935656

11. Lovejoy CA, Li W, Reisenweber S, Thongthip S, Bruno J, et al. (2012) Loss of ATRX, genome instability, and an altered DNA damage response are hallmarks of the alternative lengthening of telomeres pathway. PLoS Genet 8: e1002772. 22829774

12. Nabetani A, Ishikawa F (2011) Alternative lengthening of telomeres pathway: recombination-mediated telomere maintenance mechanism in human cells. J Biochem 149: 5–14. doi: 10.1093/jb/mvq119 20937668

13. Zhong ZH, Jiang WQ, Cesare AJ, Neumann AA, Wadhwa R, et al. (2007) Disruption of telomere maintenance by depletion of the MRE11/RAD50/NBS1 complex in cells that use alternative lengthening of telomeres. J Biol Chem 282: 29314–29322. 17693401

14. Potts PR, Yu H (2007) The SMC5/6 complex maintains telomere length in ALT cancer cells through SUMOylation of telomere-binding proteins. Nat Struct Mol Biol 14: 581–590. 17589526

15. Oganesian L, Karlseder J (2011) Mammalian 5' C-rich telomeric overhangs are a mark of recombination-dependent telomere maintenance. Mol Cell 42: 224–236. doi: 10.1016/j.molcel.2011.03.015 21504833

16. Clynes D, Jelinska C, Xella B, Ayyub H, Scott C, et al. (2015) Suppression of the alternative lengthening of telomere pathway by the chromatin remodelling factor ATRX. Nat Commun 6: 7538. doi: 10.1038/ncomms8538 26143912

17. Hu J, Hwang SS, Liesa M, Gan B, Sahin E, et al. (2012) Antitelomerase therapy provokes ALT and mitochondrial adaptive mechanisms in cancer. Cell 148: 651–663. doi: 10.1016/j.cell.2011.12.028 22341440

18. McEachern MJ, Haber JE (2006) Break-induced replication and recombinational telomere elongation in yeast. Annu Rev Biochem 75: 111–135. 16756487

19. Teng S, Chang J, McCowan B, Zakian V (2000) Telomerase-independent lengthening of yeast telomeres occurs by an abrupt Rad50p-dependent, Rif-inhibited recombinational process. Mol Cell 6: p947–952.

20. Guzman PA, Sanchez JG (1994) Characterization of telomeric regions from Ustilago maydis. Microbiology 140 (Pt 3): 551–557.

21. Yu EY, Kojic M, Holloman WK, Lue NF (2013) Brh2 and Rad51 promote telomere maintenance in Ustilago maydis, a new model system of DNA repair proteins at telomeres. DNA Repair (Amst) 12: 472–479.

22. Holloman WK (2011) Unraveling the mechanism of BRCA2 in homologous recombination. Nat Struct Mol Biol 18: 748–754. doi: 10.1038/nsmb.2096 21731065

23. Badie S, Escandell JM, Bouwman P, Carlos AR, Thanasoula M, et al. (2010) BRCA2 acts as a RAD51 loader to facilitate telomere replication and capping. Nat Struct Mol Biol 17: 1461–1469. doi: 10.1038/nsmb.1943 21076401

24. de Sena-Tomas C, Yu EY, Calzada A, Holloman WK, Lue NF, et al. (2015) Fungal Ku prevents permanent cell cycle arrest by suppressing DNA damage signaling at telomeres. Nucleic Acids Res 43: 2138–2151. doi: 10.1093/nar/gkv082 25653166

25. Wang Y, Ghosh G, Hendrickson EA (2009) Ku86 represses lethal telomere deletion events in human somatic cells. Proc Natl Acad Sci U S A 106: 12430–12435. doi: 10.1073/pnas.0903362106 19581589

26. Fisher TS, Zakian VA (2005) Ku: a multifunctional protein involved in telomere maintenance. DNA Repair (Amst) 4: 1215–1226.

27. Downs JA, Jackson SP (2004) A means to a DNA end: the many roles of Ku. Nat Rev Mol Cell Biol 5: 367–378. 15122350

28. Bautista-Espana D, Anastacio-Marcelino E, Horta-Valerdi G, Celestino-Montes A, Kojic M, et al. (2014) The telomerase reverse transcriptase subunit from the dimorphic fungus Ustilago maydis. PLoS One 9: e109981. doi: 10.1371/journal.pone.0109981 25299159

29. de Sena-Tomas C, Yu EY, Calzada A, Holloman WK, Lue NF, et al. (2015) Fungal Ku prevents permanent cell cycle arrest by suppressing DNA damage signaling at telomeres. Nucleic Acids Res.

30. Symington LS, Gautier J (2011) Double-strand break end resection and repair pathway choice. Annu Rev Genet 45: 247–271. doi: 10.1146/annurev-genet-110410-132435 21910633

31. Mao N, Kojic M, Holloman WK (2009) Role of Blm and collaborating factors in recombination and survival following replication stress in Ustilago maydis. DNA Repair (Amst) 8: 752–759.

32. Zimmermann M, Kibe T, Kabir S, de Lange T (2014) TRF1 negotiates TTAGGG repeat-associated replication problems by recruiting the BLM helicase and the TPP1/POT1 repressor of ATR signaling. Genes Dev 28: 2477–2491. doi: 10.1101/gad.251611.114 25344324

33. Nabetani A, Yokoyama O, Ishikawa F (2004) Localization of hRad9, hHus1, hRad1, and hRad17 and caffeine-sensitive DNA replication at the alternative lengthening of telomeres-associated promyelocytic leukemia body. J Biol Chem 279: 25849–25857. 15075340

34. Stavropoulos DJ, Bradshaw PS, Li X, Pasic I, Truong K, et al. (2002) The Bloom syndrome helicase BLM interacts with TRF2 in ALT cells and promotes telomeric DNA synthesis. Hum Mol Genet 11: 3135–3144. 12444098

35. O'Sullivan RJ, Arnoult N, Lackner DH, Oganesian L, Haggblom C, et al. (2014) Rapid induction of alternative lengthening of telomeres by depletion of the histone chaperone ASF1. Nat Struct Mol Biol 21: 167–174. doi: 10.1038/nsmb.2754 24413054

36. Flynn RL, Cox KE, Jeitany M, Wakimoto H, Bryll AR, et al. (2015) Alternative lengthening of telomeres renders cancer cells hypersensitive to ATR inhibitors. Science 347: 273–277. doi: 10.1126/science.1257216 25593184

37. Llorente B, Symington LS (2004) The Mre11 nuclease is not required for 5' to 3' resection at multiple HO-induced double-strand breaks. Mol Cell Biol 24: 9682–9694. 15485933

38. Shim EY, Chung WH, Nicolette ML, Zhang Y, Davis M, et al. (2010) Saccharomyces cerevisiae Mre11/Rad50/Xrs2 and Ku proteins regulate association of Exo1 and Dna2 with DNA breaks. EMBO J 29: 3370–3380. doi: 10.1038/emboj.2010.219 20834227

39. Nimonkar AV, Genschel J, Kinoshita E, Polaczek P, Campbell JL, et al. (2011) BLM-DNA2-RPA-MRN and EXO1-BLM-RPA-MRN constitute two DNA end resection machineries for human DNA break repair. Genes Dev 25: 350–362. doi: 10.1101/gad.2003811 21325134

40. Cejka P, Cannavo E, Polaczek P, Masuda-Sasa T, Pokharel S, et al. (2010) DNA end resection by Dna2-Sgs1-RPA and its stimulation by Top3-Rmi1 and Mre11-Rad50-Xrs2. Nature 467: 112–116. doi: 10.1038/nature09355 20811461

41. Banuett F, Herskowitz I (1989) Different a alleles of Ustilago maydis are necessary for maintenance of filamentous growth but not for meiosis. Proc Natl Acad Sci U S A 86: 5878–5882. 16594058

42. Kojic M, Kostrub CF, Buchman AR, Holloman WK (2002) BRCA2 homolog required for proficiency in DNA repair, recombination, and genome stability in Ustilago maydis. Mol Cell 10: 683–691. 12408834

43. Holliday R (1974) Ustilago maydis. In: King, editor. Handbook of Genetics. New York: Plenum Press. pp. 575–595.

44. Brachmann A, Weinzierl G, Kamper J, Kahmann R (2001) Identification of genes in the bW/bE regulatory cascade in Ustilago maydis. Mol Microbiol 42: 1047–1063. 11737646

45. Brachmann A, Konig J, Julius C, Feldbrugge M (2004) A reverse genetic approach for generating gene replacement mutants in Ustilago maydis. Mol Genet Genomics 272: 216–226. 15316769

46. Kamper J (2004) A PCR-based system for highly efficient generation of gene replacement mutants in Ustilago maydis. Mol Genet Genomics 271: 103–110. 14673645

47. Yu EY, Wang F, Lei M, Lue NF (2008) A proposed OB-fold with a protein-interaction surface in Candida albicans telomerase protein Est3. Nat Struct Mol Biol 15: 985–989. 19172753

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