Uloga katalitičke podjedinice RNA egzosoma Rrp6 u održavanju vijabilnosti stanica i stabilnosti stanične stijenke kvasca Saccharomyces cerevisiae pri povišenoj temperaturi

undergraduate thesis

• Title (english): Role of RNA exosome catalytic subunit Rrp6 in maintaining cell viability and cell wall stability upon heat stress
• Author: Marina Oskomić
• Mentor: Igor Stuparević (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Chemistry and Biochemistry); (Laboratory for Biochemistry); Zagreb
• Defense date and country: 2020-09-01, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

Eukariotski RNA egzosom esencijalan je i evolucijski očuvan proteinski kompleks koji procesira i degradira molekule RNA. Sastoji se od jezgre, sastavljene od devet strukturnih podjedinica, te dvije katalitičke podjedinice koje imaju 3'→5' egzoribonukleaznu aktivnost, Dis3 i Rrp6. Za razliku od Dis3, podjedinica Rrp6 nije esencijalna za vijabilnost stanica, ali delecija gena koji kodira za Rrp6 rezultira sporijim rastom i temperaturnom osjetljivošću. Rezultati ovog rada pokazali su da je defekt u rastu mutanta rrp6 pri povišenoj temperaturi posljedica oslabljene stanične stijenke, što dovodi do puknuća stanica u hipoosmolarnom okruženju. Sukladno tome, letalnost i aberantna morfologija ovog mutanta pri povišenoj temperaturi mogu se suprimirati osmotskom stabilizacijom medija. Ovaj rezultat potvrđen je korištenjem tri različite linije sojeva kvasca te uz dva načina osmotske stabilizacije medija. Budući da inaktivacija egzoribonukleazne aktivnosti Rrp6 ne rezultira temperaturnom osjetljivošću, proizlazi da je za održavanje integriteta stanične stijenke pri stresnim uvjetima odgovorna nekatalitička uloga podjedinice Rrp6.

Abstract (english)

The eukaryotic RNA exosome is an essential and conserved protein complex that processes and degrades RNA molecules. It consists of a 9-subunit structural core and 2 catalytic subunits that provide 3'→5' exoribonuclease activity, Dis3 and Rrp6. Unlike Dis3, Rrp6 is not essential for cell viability, however deletion of the gene encoding Rrp6 results in slower growth and temperature sensitivity. In this work, we show that the growth defect of rrp6 mutant at high temperature arises from a weakened cell wall structure, which leads to cell rupture in the hypoosmolar environment. Accordingly, lethality and aberrant morphology of this mutant at high temperature is suppressed by osmotic stabilization of the medium. This result was validated with three different yeast genetic backgrounds and two ways of osmotic stabilization of growth media. Since inactivation of Rrp6 exoribonuclease activity does not result in temperature sensitivity, this leads to the conclusion that a non-catalytic role of the Rrp6 subunit is responsible for maintaining cell wall integrity under stressful conditions.

• Keywords: kvasac Saccharomyces cerevisiae; RNA egzosom; Rrp6; stanična stijenka
• Keywords (english): cell wall; RNA exosome; Rrp6; yeast Saccharomyces cerevisiae
• Language: croatian
• URN:NBN: urn:nbn:hr:159:744572
• Study programme: Title: Biotechnology; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka biotehnologije (sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka biotehnologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2020-10-29 14:26:10