Évolution des centromères et séparation des chromosomes


Année de publication : 2017

Ines A Drinnenberg, Bungo Akiyoshi (2017 Aug 26)

Evolutionary Lessons from Species with Unique Kinetochores.

Progress in molecular and subcellular biology : 111-138 : DOI : 10.1007/978-3-319-58592-5_5 En savoir plus

The kinetochore is the multi-protein complex that drives chromosome segregation in eukaryotes. It assembles onto centromeric DNA and mediates attachment to spindle microtubules. Kinetochore research over the last several decades has been focused on a few animal and fungal model organisms, which revealed a detailed understanding of the composition and organization of their kinetochores. Yet, these traditional model organisms represent only a small fraction of all eukaryotes. To gain insights into the actual degree of kinetochore diversity, it is critical to extend these studies to nontraditional model organisms from evolutionarily distant lineages. In this chapter, we review the current knowledge of kinetochores across diverse eukaryotes with an emphasis on variations that arose in nontraditional model organisms. In addition, we also review the literature on species, in which the subcellular localization of kinetochores has changed from the nucleoplasm to the nuclear membrane. Finally, we speculate on the organization of the chromosome segregation machinery in an early eukaryotic ancestor to gain insights into fundamental principles of the chromosome segregation machinery, which are common to all eukaryotes.

Aruni P Senaratne, Ines A Drinnenberg (2017 Jan 22)

All that is old does not wither: Conservation of outer kinetochore proteins across all eukaryotes?

The Journal of cell biology : 291-293 : DOI : 10.1083/jcb.201701025 En savoir plus

The kinetochore drives faithful chromosome segregation in all eukaryotes, yet the underlying machinery is diverse across species. D’Archivio and Wickstead (2017. J. Cell Biol. https://doi.org/10.1083/jcb.201608043) apply sensitive homology predictions to identify proteins in kinetoplastids with similarity to canonical outer kinetochore proteins, suggesting some degree of universality in the eukaryotic kinetochore.


Année de publication : 2016

Ines A Drinnenberg, Steven Henikoff, Harmit S Malik (2016 Feb 16)

Evolutionary Turnover of Kinetochore Proteins: A Ship of Theseus?

Trends in cell biology : DOI : S0962-8924(16)00011-8 En savoir plus

The kinetochore is a multiprotein complex that mediates the attachment of a eukaryotic chromosome to the mitotic spindle. The protein composition of kinetochores is similar across species as divergent as yeast and human. However, recent findings have revealed an unexpected degree of compositional diversity in kinetochores. For example, kinetochore proteins that are essential in some species have been lost in others, whereas new kinetochore proteins have emerged in other lineages. Even in lineages with similar kinetochore composition, individual kinetochore proteins have functionally diverged to acquire either essential or redundant roles. Thus, despite functional conservation, the repertoire of kinetochore proteins has undergone recurrent evolutionary turnover.


Année de publication : 2014

Ines A Drinnenberg, Dakota deYoung, Steven Henikoff, Harmit Singh Malik (2014 Sep 24)

Recurrent loss of CenH3 is associated with independent transitions to holocentricity in insects.

eLife : DOI : 10.7554/eLife.03676 En savoir plus

Faithful chromosome segregation in all eukaryotes relies on centromeres, the chromosomal sites that recruit kinetochore proteins and mediate spindle attachment during cell division. The centromeric histone H3 variant, CenH3, is the defining chromatin component of centromeres in most eukaryotes, including animals, fungi, plants, and protists. In this study, using detailed genomic and transcriptome analyses, we show that CenH3 was lost independently in at least four lineages of insects. Each of these lineages represents an independent transition from monocentricity (centromeric determinants localized to a single chromosomal region) to holocentricity (centromeric determinants extended over the entire chromosomal length) as ancient as 300 million years ago. Holocentric insects therefore contain a CenH3-independent centromere, different from almost all the other eukaryotes. We propose that ancient transitions to holocentricity in insects obviated the need to maintain CenH3, which is otherwise essential in most eukaryotes, including other holocentrics.