BackgroundThe centromere is a specialized chromosomal locus that forms the basis for the assembly of a multi-protein complex, the kinetochore and ensures faithful chromosome segregation during every cell division. The repetitive nature of the underlying centromeric sequence represents a major obstacle for high-resolution mapping of protein binding using methods that rely on annotated genomes. Here, we present a novel microscopy-based approach called “APEX-chromatin fibers” for localizing protein binding over the repetitive centromeric sequences at kilobase resolution.ResultsBy fusing centromere factors of interest to ascorbate peroxidase, we were able to label their binding profiles on extended chromatin fibers with biotin marks. We applied APEX-chromatin fibers to at least one member of each CCAN complex, most of which show a localization pattern different from CENP-A but within the CENP-A delineated centromeric domain. Interestingly, we describe here a novel characteristic of CENP-I and CENP-B that display extended localization beyond the CENP-A boundaries.ConclusionsOur approach was successfully applied for mapping protein association over centromeric chromatin, revealing previously undescribed localization patterns. In this study, we focused on centromeric factors, but we believe that this approach could be useful for mapping protein binding patterns in other repetitive regions.Electronic supplementary materialThe online version of this article (10.1186/s13072-018-0237-6) contains supplementary material, which is available to authorized users.
Meiotic processes are potentially dangerous to genome stability and could be disastrous if activated in proliferative cells. Here we show that two key meiosis-defining proteins, the double strand break-forming topoisomerase Spo11 and the meiotic cohesin Rec8, can dismantle centromeres. This dismantlement is normally observable only in mutant cells lacking the telomere bouquet, which provides a nuclear microdomain conducive to centromere reassembly 1 ; however, overexpression of Spo11 or Rec8 leads to levels of centromere dismantlement that cannot be countered by the bouquet. Specific nucleosome remodeling factors mediate centromere dismantlement by Spo11 and Rec8. Remarkably, ectopic expression of either protein in proliferating cells leads to mitotic kinetochore loss in both fission yeast and human cells. Hence, while centromeric chromatin has been characterized as extraordinarily stable, Spo11 and Rec8 challenge this stability, and may jeopardize kinetochores in the increasing number of cancers known to express meiotic proteins.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.