Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.660283
Title: Analysis of the function of the Lsm8 protein complex in Saccharomyces cerevisiae
Author: Page, David
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 2002
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Abstract:
To enter the spliceosome, U6 snRNP must associate with the U4 snRNP to form a U4/U6 di-snRNP. This involves RNA-RNA interactions between U4 and U6 RNAs, as the two have extensive sequence complementary and form Watson-Crick base-pair interactions over their length. During splicing, the U4 snRNP dissociates from the U6 snRNP and U6 snRNA undergoes several structural rearrangements. Therefore, U4 and U6 snRNA must be reannealed following spliceosome disassembly in order to recycle the factors back into the splicing pathway. A group of seven proteins, Lsm2-Lsm8p, has previously been identified that interact with U6 snRNA and are essential for U6 snRNA stability and pre-mRNA splicing in the yeast Saccharomyces cerevisiae. In this thesis the Lsm (like-Sm) proteins have been produced either as recombinant protein in E. coli or as the product of a coupled in vitro transcription/translation reaction. Using these proteins it has been demonstrated that the Lsm proteins can facilitate U4/U6 RNA duplex formation. Another U6-ascoiated protein, Prp24p, did not facilitate U4/U6 duplex formation in the absence of the Lsm proteins. This was in contrast to previous reports suggesting a role for Prp24p in U4/U6 annealing. Prp24p is, however, required when the 3’ terminal Lsm binding site is deleted from U6 snRNA. Evidence is presented suggesting that the Lsm8 complex can facilitate U4/U6 duplex formation in vivo as well as in vitro. In particular, Lsm6p appears to be essential for stable U4/U6 duplex formation, whereas Lsm7p does not. The data presented, therefore, suggest a model where the Lsm8 complex, in particular Lsm6p, is sufficient and necessary for U4/U6 duplex formation.  Other factors such as Prp24p may facilitate this process, but are not essential for it to occur.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.660283  DOI: Not available
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