Fungal Ku Prevents Permanent Cell Cycle Arrest by Suppressing DNA Damage Signaling at Telomeres

Overview

Journal Nucleic Acids Res

Publisher Oxford University Press

Specialty Biochemistry

Date 2015 Feb 6

PMID 25653166

Citations 13

Authors

Carmen de Sena-Tomas

Eun Young Yu

Arturo Calzada

William K Holloman

Neal F Lue

Jose Perez-Martin

Affiliations

Soon will be listed here.

Abstract

The Ku heterodimer serves in the initial step in repairing DNA double-strand breaks by the non-homologous end-joining pathway. Besides this key function, Ku also plays a role in other cellular processes including telomere maintenance. Inactivation of Ku can lead to DNA repair defects and telomere aberrations. In model organisms where Ku has been studied, inactivation can lead to DNA repair defects and telomere aberrations. In general Ku deficient mutants are viable, but a notable exception to this is human where Ku has been found to be essential. Here we report that similar to the situation in human Ku is required for cell proliferation in the fungus Ustilago maydis. Using conditional strains for Ku expression, we found that cells arrest permanently in G2 phase when Ku expression is turned off. Arrest results from cell cycle checkpoint activation due to persistent signaling via the DNA damage response (DDR). Our results point to the telomeres as the most likely source of the DNA damage signal. Inactivation of the DDR makes the Ku complex dispensable for proliferation in this organism. Our findings suggest that in U. maydis, unprotected telomeres arising from Ku depletion are the source of the signal that activates the DDR leading to cell cycle arrest.

Citing Articles

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Ustilago maydis Trf2 ensures genome stability by antagonizing Blm-mediated telomere recombination: Fine-tuning DNA repair factor activity at telomeres through opposing regulations.

Syed S, Aloe S, Sutherland J, Holloman W, Lue N PLoS Genet. 2024; 20(12):e1011515.

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References

Garrido E, Voss U, Muller P, Castillo-Lluva S, Kahmann R, Perez-Martin J . The induction of sexual development and virulence in the smut fungus Ustilago maydis depends on Crk1, a novel MAPK protein. Genes Dev. 2004; 18(24):3117-30. PMC: 535921. DOI: 10.1101/gad.314904. View

Cesare A, Reddel R . Alternative lengthening of telomeres: models, mechanisms and implications. Nat Rev Genet. 2010; 11(5):319-30. DOI: 10.1038/nrg2763. View

Sgarlata C, Perez-Martin J . Inhibitory phosphorylation of a mitotic cyclin-dependent kinase regulates the morphogenesis, cell size and virulence of the smut fungus Ustilago maydis. J Cell Sci. 2005; 118(Pt 16):3607-22. DOI: 10.1242/jcs.02499. View

Banuett F, Herskowitz I . Different a alleles of Ustilago maydis are necessary for maintenance of filamentous growth but not for meiosis. Proc Natl Acad Sci U S A. 1989; 86(15):5878-82. PMC: 297734. DOI: 10.1073/pnas.86.15.5878. View

Badie S, Escandell J, Bouwman P, Carlos A, Thanasoula M, Gallardo M . BRCA2 acts as a RAD51 loader to facilitate telomere replication and capping. Nat Struct Mol Biol. 2010; 17(12):1461-9. PMC: 2998174. DOI: 10.1038/nsmb.1943. View

McEachern M, Haber J . Break-induced replication and recombinational telomere elongation in yeast. Annu Rev Biochem. 2006; 75:111-35. DOI: 10.1146/annurev.biochem.74.082803.133234. View

Onel K, Koff A, Bennett R, Unrau P, Holloman W . The REC1 gene of Ustilago maydis, which encodes a 3'-->5' exonuclease, couples DNA repair and completion of DNA synthesis to a mitotic checkpoint. Genetics. 1996; 143(1):165-74. PMC: 1207251. DOI: 10.1093/genetics/143.1.165. View

Zhong Z, Jiang W, Cesare A, Neumann A, Wadhwa R, Reddel R . Disruption of telomere maintenance by depletion of the MRE11/RAD50/NBS1 complex in cells that use alternative lengthening of telomeres. J Biol Chem. 2007; 282(40):29314-22. DOI: 10.1074/jbc.M701413200. View

Zellinger B, Akimcheva S, Puizina J, Schirato M, Riha K . Ku suppresses formation of telomeric circles and alternative telomere lengthening in Arabidopsis. Mol Cell. 2007; 27(1):163-9. DOI: 10.1016/j.molcel.2007.05.025. View

10.

Mao N, Kojic M, Holloman W . Role of Blm and collaborating factors in recombination and survival following replication stress in Ustilago maydis. DNA Repair (Amst). 2009; 8(6):752-9. PMC: 2693308. DOI: 10.1016/j.dnarep.2009.02.006. View

11.

Li B, Comai L . Functional interaction between Ku and the werner syndrome protein in DNA end processing. J Biol Chem. 2000; 275(37):28349-52. DOI: 10.1074/jbc.C000289200. View

12.

Goins C, Gerik K, Lodge J . Improvements to gene deletion in the fungal pathogen Cryptococcus neoformans: absence of Ku proteins increases homologous recombination, and co-transformation of independent DNA molecules allows rapid complementation of deletion phenotypes. Fungal Genet Biol. 2006; 43(8):531-44. DOI: 10.1016/j.fgb.2006.02.007. View

13.

Wang Y, Ghosh G, Hendrickson E . Ku86 represses lethal telomere deletion events in human somatic cells. Proc Natl Acad Sci U S A. 2009; 106(30):12430-5. PMC: 2718384. DOI: 10.1073/pnas.0903362106. View

14.

Garcia-Muse T, Steinberg G, Perez-Martin J . Pheromone-induced G2 arrest in the phytopathogenic fungus Ustilago maydis. Eukaryot Cell. 2003; 2(3):494-500. PMC: 161457. DOI: 10.1128/EC.2.3.494-500.2003. View

15.

Gotta M, Laroche T, FORMENTON A, Maillet L, Scherthan H, Gasser S . The clustering of telomeres and colocalization with Rap1, Sir3, and Sir4 proteins in wild-type Saccharomyces cerevisiae. J Cell Biol. 1996; 134(6):1349-63. PMC: 2121006. DOI: 10.1083/jcb.134.6.1349. View

16.

Wei C, Skopp R, Takata M, Takeda S, Price C . Effects of double-strand break repair proteins on vertebrate telomere structure. Nucleic Acids Res. 2002; 30(13):2862-70. PMC: 117051. DOI: 10.1093/nar/gkf396. View

17.

Dewar J, Lydall D . Pif1- and Exo1-dependent nucleases coordinate checkpoint activation following telomere uncapping. EMBO J. 2010; 29(23):4020-34. PMC: 3020640. DOI: 10.1038/emboj.2010.267. View

18.

Funabiki H, Hagan I, Uzawa S, Yanagida M . Cell cycle-dependent specific positioning and clustering of centromeres and telomeres in fission yeast. J Cell Biol. 1993; 121(5):961-76. PMC: 2119680. DOI: 10.1083/jcb.121.5.961. View

19.

Becht P, Konig J, Feldbrugge M . The RNA-binding protein Rrm4 is essential for polarity in Ustilago maydis and shuttles along microtubules. J Cell Sci. 2006; 119(Pt 23):4964-73. DOI: 10.1242/jcs.03287. View

20.

Buis J, Wu Y, Deng Y, Leddon J, Westfield G, Eckersdorff M . Mre11 nuclease activity has essential roles in DNA repair and genomic stability distinct from ATM activation. Cell. 2008; 135(1):85-96. PMC: 2645868. DOI: 10.1016/j.cell.2008.08.015. View