title: Protein-RNA interactions in centromeric chromatin creator: Dolejs, Vojtech subject: ddc-500 subject: 500 Natural sciences and mathematics subject: ddc-570 subject: 570 Life sciences description: Chromosome segregation is a complex and tightly regulated process that is necessary for proper cell division. Chromosomes are aligned at the equatorial plate and transported to nascent daughter cells using motor proteins and microtubules. They are attached to the microtubules by a multiprotein complex, the kinetochore. Kinetochores are anchored to the centromeric regions of the chromosome. These regions consist of repetitive noncoding DNA which forms the centromeric heterochromatin and is embedded in larger regions of noncoding pericentromeric heterochromatin. Centromeres are not defined by an underlying DNA sequence, but rather by the epigenetic marker Cenp-A, a histone H3 variant specific for centromeres. Cenp-A, or Cid in Drosophila melanogaster (fruit fly), together with its loading factor Cal1 and the Cenp-C protein form the basis of the inner kinetochore complex. The outer kinetochore then connects to the spindle microtubule. This process requires the presence of noncoding RNAs. These RNAs are transcribed from the pericentromeric regions and colocalise with the inner parts of the kinetochore. The absence of these RNAs leads to chromosome segregation defects, but their exact function as well as their interaction partners are not well described. These defects are observed not just in Drosophila melanogaster, but also in every other organism that has been researched to date. In this work, I investigated the interaction of centromeric proteins of Drosophila melanogaster with centromeric RNA using biochemical assays (EMSA) and mass spectrometry (HDX-MS). I overexpressed and purified proteins as well as in vitro transcribed RNAs. I observed the interaction of kinetochore proteins and centromeric RNA with focus on Cal1 and satellite RNA. I demonstrated that Cal1 fragments are RNA-binding using EMSA. However, HDX-MS was not sufficient to measure the details of the interaction, as addition of RNA did not significantly change the deuteration pattern of the protein fragments. I observed that Cal1 is unfolded and the fragment I worked with is a promiscuous RNA-binder. date: 2024 type: Dissertation type: info:eu-repo/semantics/doctoralThesis type: NonPeerReviewed format: application/pdf identifier: https://archiv.ub.uni-heidelberg.de/volltextserverhttps://archiv.ub.uni-heidelberg.de/volltextserver/35344/1/Dissertation%20Dolej%C5%A1.pdf identifier: DOI:10.11588/heidok.00035344 identifier: urn:nbn:de:bsz:16-heidok-353444 identifier: Dolejs, Vojtech (2024) Protein-RNA interactions in centromeric chromatin. [Dissertation] relation: https://archiv.ub.uni-heidelberg.de/volltextserver/35344/ rights: info:eu-repo/semantics/openAccess rights: Please see front page of the work (Sorry, Dublin Core plugin does not recognise license id) language: eng