Cytoplasmic mRNA-containing granules in eukaryotic cells play key roles inthe storage, localisation and degradation of mRNA. In yeast, depletion of glucoseleads to the rapid inhibition of translation initiation and consequent appearance of Pbodiesand EGP-bodies. P-bodies contain factors of the mRNA decay pathway andtherefore, are likely to be sites in which mRNAs targeted for degradation arelocalised. In contrast, EGP-bodies lack decay components and contain onlytranslation initiation factors and RNA binding proteins. Thus EGP-bodies have beensuggested to be storage repositories for mRNAs that need to be rapidly translatedfollowing glucose readdition. In this study we utilised the m-TAG system to investigate the localisation ofendogenous MS2-tagged mRNAs with P-bodies and EGP-bodies. A triplefluorescent labelled system developed show that a class of unregulated mRNAslocalised into P-bodies following glucose starvation. It was also observed that thesespecific abundant classes of mRNAs can be found in aggregates prior to any cellularstress and upon glucose starvation these aggregates coalesce into larger granules thatcolocalise with P-body components. This coalescence of mRNA aggregatesfollowing glucose starvation does not rely upon the recruitment of mRNA decayfactors and appears to precede this event. Indeed mRNAs in mutants deficient in Pbodyformation still develop large aggregates following glucose stress. In unstressedcells it appears that the mRNA granules are implicated in high-level translation ofthese specific abundant mRNAs. Following the inhibition of translation initiation inresponse to stress, these granules nucleate P-body formation via aggregation and therecruitment of mRNA decay factors.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:564294 |
| Date | January 2012 |
| Creators | Lui, Jennifer |
| Contributors | Ashe, Mark; Crosthwaite, Susan |
| Publisher | University of Manchester |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | https://www.research.manchester.ac.uk/portal/en/theses/investigation-into-the-localisation-of-mrna-into-cytoplasmic-granules-followingglucose-starvation-in-saccharomyces-cerevisiae(bf2a8964-fbc9-4cbe-ad0d-3e456b577eae).html |
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