Carolin Goldhardt (Martin-Luther-Universität Halle-Wittenberg)
Carolin Goldhardt's Master thesis was awarded with the Prize for the Best Plant Science Master Thesis, which was carried out at Martin-Luther-Universität Halle-Wittenberg in the year 2024 with the title:
Study on the mitochondrial localisation of the protein mTERF21 and on RNAs associated with mTERF21 in vivo in Arabidopsis thaliana
Using GFP tagging of the RNA-binding protein mTERF21, this work shows the association of the mitochondrial mTERF21 protein with multiple mRNAs and its presence in distinct foci within mitochondria.
Plant mitochondria are known for their highly complex RNA metabolism, involving hundreds of nucleus-encoded proteins that contribute to mitochondrial gene expression. Many of these proteins are part of the mitochondrial transcription termination factor (mTERF) family, whose members are also found in animal mitochondria, but which substantially expanded in land plants. For very few plant mTERFs has their exact molecular function been identified. While some were reported to indeed act as transcription termination factors, others were found to function in the splicing of organellar mRNAs.
To gain insight into the role of the mTERF family protein mTERF21, which in Arabidopsis is essential, an Arabidopsis line expressing a pmTERF21::mTERF21-GFP construct in an mterf21 loss-of-function background was used for localization studies and for RNA co-immunoprecipitation (RIP) experiments. These RIP experiments found several mitochondrial RNAs to associate with mTERF21 in vivo. Analyses of mTERF21-GFP localization by confocal microscopy detected GFP accumulation in distinct foci within mitochondria. This distribution of GFP was clearly different from that seen in a control line expressing GFP fused to a mitochondrial transit peptide. Accordingly, mitochondrial RNA metabolism involving mTERF21 might be restricted to a specific mitochondrial sub-compartment. To pave the way for further investigations of this hypothesis, a collection of Arabidopsis lines expressing fusions of different RNA- and DNA-binding proteins to fluorescent proteins has been created.
The thesis was supervised by Theresa Schoeller and Kristina Kühn in a project associated with RTG2498; the mTERF21-GFP line was provided by Minsoo Kim and Elizabeth Vierling (UMass Amherst).
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Carolin Goldhardt conducted this work at the institute of biology, department of Cell Physiology in the working group of Prof. Dr. Kristina Kühn.