Elucidation of the functional role of A. thaliana KNL2 in epigenetic regulation of kinetochore assembly in plants

• Applicant: Dr. Inna Lermontova
• Subject Area: Plant Genetics and Genomics
• Term: from 2018 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 417658620

In most eukaryotic organisms correct segregation of chromosomes during cell divisions requires presence of the centromeric histone H3 variant (cenH3). Loading of cenH3 to centromeres is a multi-step process which does not depend on specific DNA sequences, but depends on the epigenetic status of centromeric chromatin and on different assembly factors. Deregulated expression of cenH3 or its improper loading to centromeres results in mitotic and meiotic defects in plants and animals. Although numerous publications on the regulation of cenH3 loading to centromeres in animals (less is known from plants) exist, the mechanism of this multi-step process has to be elucidated more in detail. Previously we have identified and characterized the first plant cenH3 assembly factor KNL2. We showed that the knockout of KNL2 results in a reduced level of cenH3 at centromeres, reduced DNA methylation, defects in mitosis and meiosis followed by reduced growth rate and fertility. In the frame of the applied project we aim to elucidate the epigenetic regulation of cenH3 loading and kinetochore assembly using Arabidopsis thaliana as a model and to decipher the role of KNL2 proteins in this process. We will study i) how in epigenetic mutants an altered level of DNA and H3K9 methylation influences the centromere loading of cenH3 and other kinetochore proteins, ii) how a knockout of the cenH3 assembly factor KNL2 influences the methylation of the global Arabidopsis genome, iii) how the directed targeting of epigenetic factors like MET1 and VIM1 to centromeres regulate kinetochore assembly and function during different stages of the cell cycle. Such knowledge is essential i) to understand the mechanism of the assembly and function of the kinetochore protein complex at the centromeres, ii) to generate artificial centromeres for chromosome engineering and iii) to improve the efficiency of generating double haploids for an accelerated plant breeding process based on centromere manipulation.

• DFG Programme: Research Grants