Description
- Abstract:
- Transposons are parasitic DNA sequences that pose threats to genome stability across a range of eukaryotes. To defend against transposition into essential genes and destabilizing transposon proliferation, eukaryotes regulate transposon transcription. Gene regulation is often achieved via chromatin modifications of histone proteins and DNA. Through methylation of histone 3 lysine 9 (H3K9), the eukaryotic cell can silence the transcription of transposons as a defense system. This fundamental H3K9 methylation is mediated by H3K9 methyltransferase enzymes that are responsible for efficient and precise modification of silenced regions. While various kingdoms use the same catalytic H3K9 methyltransferase domain, plants have evolved a novel H3K9 methyltransferase class of SUVH proteins. However, why the single SUVH protein present in green algae has expanded and diversified into a large family of proteins in the flowering plant Arabidopsis thaliana is unclear. In this work, I identify unique features of the SUVH6 clade of H3K9 methyltransferases and test the functionalities of these features through a genetic approach. I demonstrate that SUVH6 clade proteins contain longer, likely disordered amino-terminal extensions with a novel motif that function in nuclear localization and activity at preferred loci. My results provide insights into the diversification of chromatin-modifying enzymes and how these enzymes can gain new functions over evolution.
- Notes:
- Thesis (Ph. D.)--Brown University, 2020
Citation
Kotak, Jenna Elizabeth,
"Diversification of the SUVH6 Clade of Histone 3 Lysine 9 Methyltransferases in Flowering Plants"
(2020).
Molecular Biology, Cell Biology, and Biochemistry Theses and Dissertations.
Brown Digital Repository. Brown University Library.
https://repository.library.brown.edu/studio/item/bdr:rph7zwtk/
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Molecular Biology, Cell Biology, and Biochemistry Theses and Dissertations
Theses and Dissertations for the Molecular Biology, Cell Biology, and Biochemistry department....