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The CENP-A N-Tail Confers Epigenetic Stability to Centromeres via the CENP-T Branch of the CCAN in Fission Yeast

2015; Elsevier BV; Volume: 25; Issue: 3 Linguagem: Inglês

10.1016/j.cub.2014.11.060

1879-0445

H. Diego Folco, Christopher S. Campbell, Karen May, Celso A. Espinoza, Karen Oegema, Kevin Hardwick, Shiv I. S. Grewal, Arshad Desai,

Plant Molecular Biology Research

In most eukaryotes, centromeres are defined epigenetically by presence of the histone H3 variant CENP-A [1Catania S. Allshire R.C. Anarchic centromeres: deciphering order from apparent chaos.Curr. Opin. Cell Biol. 2014; 26: 41-50Crossref PubMed Scopus (20) Google Scholar, 2Müller S. Almouzni G. A network of players in H3 histone variant deposition and maintenance at centromeres.Biochim. Biophys. Acta. 2014; 1839: 241-250Crossref PubMed Scopus (44) Google Scholar, 3Fukagawa T. Earnshaw W.C. The centromere: chromatin foundation for the kinetochore machinery.Dev. Cell. 2014; 30: 496-508Abstract Full Text Full Text PDF PubMed Scopus (279) Google Scholar]. CENP-A-containing chromatin recruits the constitutive centromere-associated network (CCAN) of proteins, which in turn directs assembly of the outer kinetochore to form microtubule attachments and ensure chromosome segregation fidelity [4Verdaasdonk J.S. Bloom K. Centromeres: unique chromatin structures that drive chromosome segregation.Nat. Rev. Mol. Cell Biol. 2011; 12: 320-332Crossref PubMed Scopus (149) Google Scholar, 5Perpelescu M. Fukagawa T. The ABCs of CENPs.Chromosoma. 2011; 120: 425-446Crossref PubMed Scopus (149) Google Scholar, 6Cheeseman I.M. Desai A. Molecular architecture of the kinetochore-microtubule interface.Nat. Rev. Mol. Cell Biol. 2008; 9: 33-46Crossref PubMed Scopus (689) Google Scholar]. Whereas the mechanisms that load CENP-A at centromeres are being elucidated, the functions of its divergent N-terminal tail remain enigmatic [7Sullivan K.F. Hechenberger M. Masri K. Human CENP-A contains a histone H3 related histone fold domain that is required for targeting to the centromere.J. Cell Biol. 1994; 127: 581-592Crossref PubMed Scopus (363) Google Scholar, 8Chen Y. Baker R.E. Keith K.C. Harris K. Stoler S. Fitzgerald-Hayes M. The N terminus of the centromere H3-like protein Cse4p performs an essential function distinct from that of the histone fold domain.Mol. Cell. Biol. 2000; 20: 7037-7048Crossref PubMed Scopus (122) Google Scholar, 9Takayama Y. Sato H. Saitoh S. Ogiyama Y. Masuda F. Takahashi K. Biphasic incorporation of centromeric histone CENP-A in fission yeast.Mol. Biol. Cell. 2008; 19: 682-690Crossref PubMed Scopus (82) Google Scholar, 10Ravi M. Chan S.W. Haploid plants produced by centromere-mediated genome elimination.Nature. 2010; 464: 615-618Crossref PubMed Scopus (361) Google Scholar, 11Fachinetti D. Folco H.D. Nechemia-Arbely Y. Valente L.P. Nguyen K. Wong A.J. Zhu Q. Holland A.J. Desai A. Jansen L.E. Cleveland D.W. A two-step mechanism for epigenetic specification of centromere identity and function.Nat. Cell Biol. 2013; 15: 1056-1066Crossref PubMed Scopus (182) Google Scholar, 12Torras-Llort M. Medina-Giró S. Moreno-Moreno O. Azorín F. A conserved arginine-rich motif within the hypervariable N-domain of Drosophila centromeric histone H3 (CenH3) mediates BubR1 recruitment.PLoS ONE. 2010; 5: e13747Crossref PubMed Scopus (9) Google Scholar]. Here, we employ the well-studied fission yeast centromere [13Pidoux A.L. Allshire R.C. Kinetochore and heterochromatin domains of the fission yeast centromere.Chromosome Res. 2004; 12: 521-534Crossref PubMed Scopus (99) Google Scholar, 14Folco H.D. Pidoux A.L. Urano T. Allshire R.C. Heterochromatin and RNAi are required to establish CENP-A chromatin at centromeres.Science. 2008; 319: 94-97Crossref PubMed Scopus (227) Google Scholar, 15Ishii K. Conservation and divergence of centromere specification in yeast.Curr. Opin. Microbiol. 2009; 12: 616-622Crossref PubMed Scopus (12) Google Scholar, 16Yamagishi Y. Sakuno T. Goto Y. Watanabe Y. Kinetochore composition and its function: lessons from yeasts.FEMS Microbiol. Rev. 2014; 38: 185-200Crossref PubMed Scopus (30) Google Scholar] to investigate the function of the CENP-A (Cnp1) N-tail. We show that alteration of the N-tail does not affect Cnp1 loading at centromeres, outer kinetochore formation, or spindle checkpoint signaling but nevertheless elevates chromosome loss. N-tail mutants exhibited synthetic lethality with an altered centromeric DNA sequence, with rare survivors harboring chromosomal fusions in which the altered centromere was epigenetically inactivated. Elevated centromere inactivation was also observed for N-tail mutants with unaltered centromeric DNA sequences. N-tail mutants specifically reduced localization of the CCAN proteins Cnp20/CENP-T and Mis6/CENP-I, but not Cnp3/CENP-C. Overexpression of Cnp20/CENP-T suppressed defects in an N-tail mutant, suggesting a link between reduced CENP-T recruitment and the observed centromere inactivation phenotype. Thus, the Cnp1 N-tail promotes epigenetic stability of centromeres in fission yeast, at least in part via recruitment of the CENP-T branch of the CCAN.