Epigenetic regulation of centromeric chromatin and its role in chromosome segregation
Final Report Abstract
Centromeres are essential for chromosome segregation during mitosis and meiosis, by providing an anchor point for kinetochore formation and chromosome-spindle interaction. Centromeric DNA is not conserved and epigenetic mechanisms are thought to determine centromere identity and inheritance. The histone H3-variant CENP-A marks centromeric chromatin epigenetically and is absolutely required for kinetochore formation; however, we still do not fully understand CENP-A regulation and loading. To better understand CENP-A loading we analyzed interacting proteins and post-transcriptional modifications that influence CENP-A loading behavior in Drosophila melanogaster. We found that CENP-A loading to centromeres is intimately linked to cell cycle regulation and mitotic length by a direct interaction with the spindle assembly checkpoint protein ZW10 and the CENP-A loading factor CAL1. In addition, specific tRNA and their methylation by the RNA methyltransferase DNMT2 are also required for accurate assembly of centromeric chromatin. Interestingly, we also found that stem cells segregate centromere components asymmetrically during division, indicating that centromeres play a crucial role in stem cell maintenance and differentiation. CENP-A misexpression can cause chromosome segregation defects by causing ectopic kinetochores outside of centromeric regions. To better understand how ectopic CENP-A loading can occur, we studied CENP-A loading in CENP-A overexpressing cells and discovered that the chromatin remodeling complex NuRD is required for CENP-A deposition along the chromosome arms, linking these two markers of certain human cancer types to a common molecular pathway.
Publications
- The DEK oncoprotein is a Su(var) that is essential to heterochromatin integrity. Genes and Dev. 2011 Apr 1;25(7):673-8
Kappes F, Waldmann T, Mathew V, Yu J, Zhang L, Khodadoust MS, Chinnaiyan AM, Luger K, Erhardt S, Schneider R, Markovitz DM
(See online at https://doi.org/10.1101/gad.2036411) - Repetitive centromeric satellite RNA is essential for kinetochore formation and cell division. J. Cell Biol. 2014 Nov 10;207(3):335-49
Rošić S, Köhler F, Erhardt S
(See online at https://doi.org/10.1083/jcb.201404097) - The E3 ligase CUL3/RDX controls centromere maintenance by ubiquitylating and stabilizing CENP-A in a CAL1-dependent manner. Dev Cell 28, 508-519 (2014)
Bade, D., Pauleau, A. L., Wendler, A. & Erhardt, S.
(See online at https://doi.org/10.1016/j.devcel.2014.01.031) - The histone-fold protein CHRAC14 influences chromatin composition in response to DNA damage. Cell Reports 7, 321-330 (2014)
Mathew, V. et al.
(See online at https://doi.org/10.1016/j.celrep.2014.03.008) - Chromatin-associated noncoding RNAs in development and inheritance. Wiley Interdiscip Rev RNA. 2017 Aug 25
Acharya S, Hartmann M, Erhardt S
(See online at https://doi.org/10.1002/wrna.1435) - Post-translational Modifications of Centromeric Chromatin. Prog Mol Subcell Biol. 2017; 56:213-231
García Del Arco A, Erhardt S
(See online at https://doi.org/10.1007/978-3-319-58592-5_9) - Asymmetric CENP-A loading marks intestinal stem cells and reveals a non-mitotic function for CENP-A and its loading machinery. CellReports 2018 Feb 20;22(8):1982-1993
Garcia del Arco A, B.Edgar, Erhardt S
(See online at https://doi.org/10.1016/j.celrep.2018.01.079) - Centromeric CENP-A loading requires accurate mitotic timing, which is linked to checkpoint proteins. PlosGenetics 2019
Pauleau A, Kajtez J, Bergner A, Erhardt S
(See online at https://doi.org/10.1371/journal.pgen.1008380)
