Zipprich, Jakob Theophil. The role of TNRC6 proteins in gene silencing. 2013, PhD Thesis, University of Basel, Faculty of Science.
Official URL: http://edoc.unibas.ch/diss/DissB_10589
In this work, we investigate the role of GW182 proteins in miRNA-mediated repression. We demonstrate that the repression mediated by TNRC6C is due to a combination of effects on the mRNA level and mRNA translation. Through deletion analysis, we could identify the C-terminal part of TNRC6C as a key effector domain mediating repression of protein synthesis. Furthermore, we show that two unstructured regions located within the C-terminal part are responsible for the effect. We give evidence for a direct interaction of TNRC6C with PABP and CNOT1. Both interactions are mediated by the C-terminal effector domain, however by different sub-fragments. While repression of protein synthesis is independent of the interaction with PABP, it relies on the interaction with the CCR4–NOT complex. The interaction is mediated by GW-repeats which are located in the two regions flanking the RRM. Finally, we show that the C-terminal effector domain is able to induce repression upon tethering not only of poly(A)+ but also of poly(A)–reporters.
Our results characterize the role of GW182 proteins in gene silencing and clarify some of the recent contradictions about the diverse proposals for the mode of action of miRNAs. The identified effector motifs function as important mediators of miRNA-induced silencing and reveal the recruitment of the CCR4–NOT machinery to the RNA-induced silencing complex. In addition to inducing mRNA decay, the recruitment of GW182 also results in inhibition of mRNA translation independently of deadenylation.
|Committee Members:||Meister, Gunter|
|Faculties and Departments:||09 Associated Institutions > Friedrich Miescher Institut FMI|
|Bibsysno:||Link to catalogue|
|Number of Pages:||116 S.|
|Last Modified:||30 Jun 2016 10:54|
|Deposited On:||28 Nov 2013 09:06|
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