Live imaging of root tip cells of A. thaliana transformed with the EYFP-AtKNL-C fusion

construct (Lermontova et al., 2013, featured by The Plant Cell [link]dx.doi.org/10.1105/tpc.113.250910).

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Knockdown of NASPSIM3 in A. thaliana impairs CenH3 loading (LeGoff et al., 2020, press release: [link]https://www.eurekalert.org/pub_releases/2019-10/liop-dtc102119.php).

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Crossing of A. thaliana mutant for the kinetochore protein KNL2 with wild-type results in the generation of haploids (WO2017/067714, press release: www.eurekalert.org/pub_releases/2019-10/liop-dtc102119.php).

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Arbeitsgruppe Kinetochor-Biologie

Leitung: Inna Lermontova

 

Centromeres are specialized chromosomal domains which are composed of centromeric DNA, often enriched in satellite repeats, and a large protein complex, the “kinetochore”. Proper assembly of the kinetochore complex is a prerequisite for the correct segregation of chromosomes during mitotic and meiotic divisions and, consequently, for genome stability in all eukaryotic organisms.

Deposition of the centromeric histone H3 variant CenH3 at the centromeric region is a prerequisite for correct assembly and function of the kinetochore complex in most eukaryotes. CenH3 deposition depends on cenH3 assembly factors, like KNL2 (Lermontova et al., 2013; Sandmann et al., 2017), chaperones (e.g. NASPSIM3, Le Goff et al., 2020), transcription of the centromeric repeats and the epigenetic status of centromeric chromatin. Specific manipulation of the CenH3 assembly factor KNL2 yielded double haploids in Arabidopsis thaliana (I. Lermontova, WO2017/067714). The production of double haploids enables a shortcut to achieve genome homozygosity in plant breeding.

To date, over 100 kinetochore components have been identified and many of them were functionally characterized in yeast, Drosophila, and mammals. In plants, however, only around 20 kinetochore proteins have been described so far, and only a few of them were characterized functionally. Moreover, the mechanism of kinetochore assembly that was studied intensively in yeast and animals during the last decade, is still poorly understood in plants.

 

Our main research goals are:

  1. Elucidation of the mechanism of kinetochore assembly and function in plants using the model plant A. thaliana and various crop plant species.

  2. Application of the gained knowledge for efficient haploid induction in crop species.

 

To achieve these goals, the research group Kinetochore Biology focuses on:

  • Identification and functional characterization of novel components of the plant kinetochore complex.

  • Characterisation of interaction networks of KNL2 and NASPSIM3 proteins.

  • Elucidation of the mechanism of epigenetic regulation of kinetochore assembly.

  • Optimization of the KNL2-based haploid induction approach in Arabidopsis and elucidation of its mechanism.

  • Transfer of the KNL2-based haploid induction approach to crop species.

     

Model for the localization and function of the KNL2 and CENP-C of plants in cenH3 loading and kinetochore assembly (Sandmann et al., 2017, featured by The Plant Cell doi: [link]10.1105/tpc.17.00035).