Integrity of the human centromere DNA repeats is protected by CENP-A, CENP-C, and CENP-T.
Centromeres are highly specialized chromatin domains that enable chromosome segregation and orchestrate faithful cell division. Human centromeres are composed of tandem arrays of α-satellite DNA, which spans up to several megabases. Little is known about the mechanisms that maintain integrity of the long arrays of α-satellite DNA repeats. Here, we monitored centromeric repeat stability in human cells using chromosome-orientation fluorescent in situ hybridization (CO-FISH). This assay detected aberrant centromeric CO-FISH patterns consistent with sister chromatid exchange at the frequency of 5% in primary tissue culture cells, whereas higher levels were seen in several cancer cell lines and during replicative senescence. To understand the mechanism(s) that maintains centromere integrity, we examined the contribution of the centromere-specific histone variant CENP-A and members of the constitutive centromere-associated network (CCAN), CENP-C, CENP-T, and CENP-W. Depletion of CENP-A and CCAN proteins led to an increase in centromere aberrations, whereas enhancing chromosome missegregation by alternative methods did not, suggesting that CENP-A and CCAN proteins help maintain centromere integrity independently of their role in chromosome segregation. Furthermore, superresolution imaging of centromeric CO-FISH using structured illumination microscopy implied that CENP-A protects α-satellite repeats from extensive rearrangements. Our study points toward the presence of a centromere-specific mechanism that actively maintains α-satellite repeat integrity during human cell proliferation.
Laboratory of Chromosome and Cell Biology, The Rockefeller University, New York, NY 10065 funabih@rockefeller.edu sgiunta@rockefeller.edu.
Simona
S
Giunta
Laboratory of Chromosome and Cell Biology, The Rockefeller University, New York, NY 10065 funabih@rockefeller.edu sgiunta@rockefeller.edu.
Hironori
0000-0003-4831-4087
H
Funabiki
D000375:Aging / Q000235:genetics; D002455:Cell Division; D045744:Cell Line, Tumor; D016922:Cellular Senescence / Q000235:genetics; D002503:Centromere / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D000076247:Centromere Protein A / Q000378:metabolism*; D002843:Chromatin / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism*; D020090:Chromosome Segregation; D004276:DNA, Satellite / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008853:Microscopy / Q000379:methods; D009369:Neoplasms / Q000235:genetics; D061251:Primary Cell Culture
C000619700:CENPA protein, human; C534001:CENPT protein, human; D000076247:Centromere Protein A; D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D004276:DNA, Satellite; C060905:centromere protein C
CO-FISH; cancer; centromere; genome integrity; α-satellite repeats