Doctoral defence: Vlad-Julian Piljukov “Biochemical characterization of Irc3 helicase”

On 19 September at 14:15 Vlad-Julian Piljukov will defend his doctoral thesis „Biochemical characterization of Irc3 helicase“ for obtaining the degree of Doctor of Philosophy (in Molecular Biology).

Supervisor:
Professor Juhan Sedman, University of Tartu

Oponent:
Dr. Jaakko Pohjoismäki, University of Eastern Finland (Finland)

Summary:

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Mitochondria, essential organelles responsible for most cellular energy production, possess a notable feature – they harbor a distinct and autonomous genome. If this genome becomes damaged or lost, it can lead to devastating conditions, ranging from illnesses to death. Scientists often use the baker’s yeast Saccharomyces cerevisiae to study how cells preserve their mitochondrial DNA. This yeast can survive without a functional mitochondrial genome, making it an ideal model to explore mutations that lead to death in more complex organisms. Within the confines of yeast mitochondria, many proteins participate in the preservation of the mitochondrial genome. One essential class of these proteins are helicases, enzymes that act like tiny machines, using ATP energy to crawl on and rearrange DNA and RNA molecules. One helicase found in yeast mitochondria, Irc3, has caught our attention. Irc3 is present in various yeasts but not in other organisms. Irc3 from a thermotolerant yeast called Ogataea polymorpha can function at relatively high temperatures, a desirable and rare trait in helicases. Additionally, this helicase interacts with both DNA and RNA, with a preference for working with DNA. The property of being stimulated by both DNA and RNA molecules is not common for other helicases. Our studies of Irc3 revealed its role in maintaining the mitochondrial genome, and in a recent report, it has been associated with performing the functions of an RNA helicase during the elongation phase of protein synthesis. Furthermore, distinctive attributes of Irc3 suggest a potential role in tying together the yeast DNA and RNA metabolism. Beyond the fundamental significance of the study that helps to understand the role of Irc3 in the maintenance of mitochondrial genetic material, it may present new prospects for drug discovery in the future.