Satellite DNA at the Centromere Is Dispensable for Segregation Fidelity

Roberti, Annalisa; Bensi, Mirella; Mazzagatti, Alice; Piras, Francesca M.; Nergadze, Solomon G.; Giulotto, Elena; Raimondi, Elena

doi:10.3390/genes10060469

Cited by 12 publications

(10 citation statements)

References 47 publications

(75 reference statements)

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“…It has been proposed that the occurrence of crossovers near centromeres is selectively disadvantageous because it may cause premature sister chromatid separation leading to non-disjunction events at the second meiotic division 24 . It is interesting to mention our recent observation that also mitotic segregation is not affected by the absence of centromeric satellite repeats on horse chromosome 11 44 .…”

Section: Discussionmentioning

confidence: 89%

CENP-A binding domains and recombination patterns in horse spermatocytes

Cappelletti

Piras

Badiale

et al. 2019

Sci Rep

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Centromeres exert an inhibitory effect on meiotic recombination, but the possible contribution of satellite DNA to this “centromere effect” is under debate. In the horse, satellite DNA is present at all centromeres with the exception of the one from chromosome 11. This organization of centromeres allowed us to investigate the role of satellite DNA on recombination suppression in horse spermatocytes at the stage of pachytene. To this aim we analysed the distribution of the MLH1 protein, marker of recombination foci, relative to CENP-A, marker of centromeric function. We demonstrated that the satellite-less centromere of chromosome 11 causes crossover suppression, similarly to satellite-based centromeres. These results suggest that the centromere effect does not depend on satellite DNA. During this analysis, we observed a peculiar phenomenon: while, as expected, the centromere of the majority of meiotic bivalent chromosomes was labelled with a single immunofluorescence centromeric signal, double-spotted or extended signals were also detected. Their number varied from 0 to 7 in different cells. This observation can be explained by positional variation of the centromeric domain on the two homologs and/or misalignment of pericentromeric satellite DNA arrays during homolog pairing confirming the great plasticity of equine centromeres.

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Section: Discussionmentioning

confidence: 89%

CENP-A binding domains and recombination patterns in horse spermatocytes

Cappelletti

Piras

Badiale

et al. 2019

Sci Rep

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“…The absence of satellite DNA at these centromeres also provides a unique opportunity to understand whether some typical features of mammalian centromeres depend on the presence of satellite DNA. In particular, it was possible to demonstrate that satellite DNA was not necessary for segregation fidelity of the centromere [113] and was not implicated in the suppression of meiotic recombination, which is typically exerted by the centromere [112].…”

Section: Unique Aspects Of the Horse Genomementioning

confidence: 99%

Decoding the Equine Genome: Lessons from ENCODE

Peng

Petersen

Kalbfleisch

et al. 2021

Genes

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The horse reference genome assemblies, EquCab2.0 and EquCab3.0, have enabled great advancements in the equine genomics field, from tools to novel discoveries. However, significant gaps of knowledge regarding genome function remain, hindering the study of complex traits in horses. In an effort to address these gaps and with inspiration from the Encyclopedia of DNA Elements (ENCODE) project, the equine Functional Annotation of Animal Genome (FAANG) initiative was proposed to bridge the gap between genome and gene expression, providing further insights into functional regulation within the horse genome. Three years after launching the initiative, the equine FAANG group has generated data from more than 400 experiments using over 50 tissues, targeting a variety of regulatory features of the equine genome. In this review, we examine how valuable lessons learned from the ENCODE project informed our decisions in the equine FAANG project. We report the current state of the equine FAANG project and discuss how FAANG can serve as a template for future expansion of functional annotation in the equine genome and be used as a reference for studies of complex traits in horse. A well-annotated reference functional atlas will also help advance equine genetics in the pan-genome and precision medicine era.

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“…The presence of such sequences has hampered comprehensive molecular analysis of these intriguing loci. Our discovery that equids are characterized by centromeres completely devoid of satellite DNA made these species an exceptional model system for dissecting the molecular architecture of mammalian centromeres as well as understanding the mechanisms driving centromere birth and maturation during evolution (Wade, et al 2009; Piras, et al 2010; Purgato, et al 2015; Giulotto, et al 2017; Nergadze, et al 2018; Roberti, et al 2019).…”

Section: Introductionmentioning

confidence: 99%

Neocentromere formation through Robertsonian fusion and centromere repositioning during the evolution of zebras

Cappelletti

Piras

Sola

et al. 2022

Preprint

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Centromeres are epigenetically specified by the histone H3 variant CENP-A and typically associated to highly repetitive satellite DNA. We previously discovered natural satellite-free neocentromeres in Equus caballus and E. asinus. Here, through ChIP-seq with an anti-CENP-A antibody, we found an extraordinarily high number of centromeres lacking satellite DNA in the zebras E. burchelli (15 of 22) and E. grevyi (13 of 23), demonstrating that the absence of satellite DNA at the majority of centromeres is compatible with genome stability and species survival and challenging the role of satellite DNA in centromere function. Nine neocentromeres are shared between the two species in agreement with their recent separation. We de novo assembled all neocentromeric regions and improved the reference genome of E. burchelli. Sequence analysis of the CENP-A binding domains revealed that they are LINE-1 and AT-rich with four of them showing DNA amplification. In the two zebras, satellite-free centromeres emerged from centromere repositioning or following Robertsonian fusion. In five chromosomes, the centromeric function arose near the fusion points, which are located within regions marked by traces of ancestral pericentromeric sequences. Therefore, besides centromere repositioning, Robertsonian fusions are an important source of satellite-free centromeres during evolution. Finally, in one case, a neocentromere was seeded on an inversion breakpoint. At eleven chromosomes, whose primary constrictions seemed to be associated to satellite repeats by cytogenetic analysis, neocentromeres were instead located near the ancestral inactivated satellite-based centromeres, therefore, the centromeric function has shifted away from a satellite repeat containing locus to a satellite-free new position.

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Satellite DNA at the Centromere Is Dispensable for Segregation Fidelity

Cited by 12 publications

References 47 publications

CENP-A binding domains and recombination patterns in horse spermatocytes

CENP-A binding domains and recombination patterns in horse spermatocytes

Decoding the Equine Genome: Lessons from ENCODE

Neocentromere formation through Robertsonian fusion and centromere repositioning during the evolution of zebras

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