Molecular Mechanisms of Chromosome Dynamics


Daniele Fachinetti CR1 CNRS Tel:

Figure 1 : Les centromères sont requis pour la séparation des chromosomes lors de la mitose et de la méiose. Immuno-fluorescence sur cellules humaines montrant la localisation de CENP-C et alpha-tubulin.
Figure 1: The centromeres are required for chromosome segregation during mitosis and meiosis. Immunofluorescence on human cells shows the localization of CENP-C and alpha-tubulin during the different stage of mitosis.

To maintain balance in genetic information the replicated chromosomes of the mother cell divide equally to create two daughter cells, each with a perfectly identical copy of the cellular genetic material. Delivery of chromosomes to each daughter cell during cell division is mediated by the centromere, the fundamental requisite for chromosome inheritance (Figure 1). Indeed, centromeres play a major role in chromosome segregation and cell division driving the assembly of the kinetochore, the protein complex at which the spindle attaches during mitosis and meiosis. Failure in these processes can lead to chromosome mis-segregation and, consequently, to numerical and structural alterations, which in turn can give rise to conditions such as aneuploidy and/or chromosome instability (CIN), both common features of cancer cells.

The Fachinetti lab is interested in understanding how chromosome inheritance is achieved with such high fidelity by identifying how centromeres are established, the mechanisms that drive centromere function, how their integrity is preserved across the cell cycle and the role that centromere failure plays in genome stability.

Figure 2: Overview of the strategies/techniques used to determine the mechanisms of chromosome segregation and integrity including genome editing, cell biology, cytogenetic and genome-wide techniques.
Figure 2: Overview of the strategies/techniques used to determine the mechanisms of chromosome segregation and integrity including genome editing, cell biology, cytogenetic and genome-wide techniques.

Although natural human centromeres are positioned within specific megabase chromosomal regions containing α-satellite DNA repeats, the centromere position is epigenetically specified (Nechemia-Arbely*, Fachinetti*, et al, ECR, 2012). Using gene targeting in human cells and fission yeast, we have previously demonstrated that chromatin containing the centromere-specific histone H3 variant CENP-A is the essential epigenetic mark that acts through a conserved two-step mechanism to identify, maintain and propagate centromere function indefinitely (Fachinetti et al., NCB, 2013). Additionally, we have established that centromere function is not all epigenetically derived; the binding of CENP-B, the only known mammalian centromeric DNA sequence-specific binding protein (present in all human centromeres except the Y chromosome), enhances the fidelity of human centromere function by reinforcing kinetochore formation (Fachinetti et al., Dev Cell, 2015). Our research program is based on an integrated approach that combines the use of engineered cell culture models to conditionally control the stability of endogenous proteins [with an auxin-inducible degron (AID) (Holland*, Fachinetti* et al., PNAS, 2012)] with cell imaging, cytogenetic analysis, proteomic approaches and genome-wide and single molecule technologies (Figure 2). In particular, we are currently studying the molecular mechanism for centromere identification and the importance of DNA sequences for the maintenance of centromere function and integrity. Additional work in the lab is aimed towards the characterization of components that are essential for successful kinetochore nucleation.

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Key publications

Year of publication 2021

Daniel Jeffery, Alberto Gatto, Katrina Podsypanina, Charlène Renaud-Pageot, Rebeca Ponce Landete, Lorraine Bonneville, Marie Dumont, Daniele Fachinetti, Geneviève Almouzni (2021 Mar 26)

CENP-A overexpression promotes distinct fates in human cells, depending on p53 status

Communications Biology : 4 : 1-18 : DOI : 10.1038/s42003-021-01941-5
Simona Giunta, Solène Hervé, Ryan R White, Therese Wilhelm, Marie Dumont, Andrea Scelfo, Riccardo Gamba, Cheng Kit Wong, Giulia Rancati, Agata Smogorzewska, Hironori Funabiki, Daniele Fachinetti (2021 Mar 3)

CENP-A chromatin prevents replication stress at centromeres to avoid structural aneuploidy.

Proceedings of the National Academy of Sciences of the United States of America : DOI : e2015634118

Year of publication 2020

Sebastian Hoffmann, Helena M Izquierdo, Riccardo Gamba, Florian Chardon, Marie Dumont, Veer Keizer, Solène Hervé, Shannon M McNulty, Beth A Sullivan, Nicolas Manel, Daniele Fachinetti (2020 Sep 18)

A genetic memory initiates the epigenetic loop necessary to preserve centromere position.

The EMBO journal : e105505 : DOI : 10.15252/embj.2020105505

Year of publication 2019

Marie Dumont, Riccardo Gamba, Pierre Gestraud, Sjoerd Klaasen, Joseph T Worrall, Sippe G De Vries, Vincent Boudreau, Catalina Salinas-Luypaert, Paul S Maddox, Susanne Ma Lens, Geert Jpl Kops, Sarah E McClelland, Karen H Miga, Daniele Fachinetti (2019 Nov 22)

Human chromosome-specific aneuploidy is influenced by DNA-dependent centromeric features.

The EMBO journal : e102924 : DOI : 10.15252/embj.2019102924
Simon Gemble, Anthony Simon, Carole Pennetier, Marie Dumont, Solène Hervé, Franz Meitinger, Karen Oegema, Raphaël Rodriguez, Geneviève Almouzni, Daniele Fachinetti, Renata Basto (2019 Sep 10)

Centromere Dysfunction Compromises Mitotic Spindle Pole Integrity.

Current biology : CB : 3072-3080.e5 : DOI : S0960-9822(19)30932-7
Andrea Scelfo, Daniele Fachinetti (2019 Aug 21)

Keeping the Centromere under Control: A Promising Role for DNA Methylation.

Cells : DOI : E912
All publications