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Hsp90 and its co-chaperones regulate the activity of human Argonaute2 in RNA-mediated silencing pathways

  • Author / Creator
    Pare, Justin Mathew
  • The potent ability of small, double-stranded RNAs to silence gene expression was initially reported 1998, sparking revolutions in molecular biology and genetics. Since then, intensive research into the mechanism of RNA-mediated silencing has implicated the machinery of this pathway in the post-transcriptional regulation of the majority of mammalian genes. The major RNA effectors of silencing are miRNAs, and they target mRNAs encoding proteins involved in nearly every biological process including cell division, differentiation, development and death. These small RNAs directly associate with a member of the Argonaute family of proteins to form the RISC which functions as a component of large ribonucleoprotein complexes. Considering the extent and critical nature of the proteins regulated by the miRNA pathway, the assembly and activity of RISC is most certainly subject to extensive regulation by a variety of mechanisms. Hsp90 is an essential, ubiquitous and highly abundant molecular chaperone that is conserved throughout evolution. Interactions with its vast array of client proteins are coordinated by a network of co-chaperones, and its activity results in conformational changes within the structure of these clients through a process known as the chaperone cycle. A generally accepted role for Hsp90 in that maturation of its clients involves the stabilization of an unfavorable structural intermediate. The stabilization of these intermediates allows for the activation of the client. A role for Hsp90 in the RNAi pathway was initially suggested by data demonstrating a reduced interaction between the RNAi core components hAgo2 and Dicer in the absence of Hsp90 activity. In this thesis, I have demonstrated that Hsp90 activity, together with a subset of its co-chaperones, is important for the function of the miRNA-mediated post-transcriptional gene silencing machinery.

  • Subjects / Keywords
  • Graduation date
    2011-11
  • Type of Item
    Thesis
  • Degree
    Doctor of Philosophy
  • DOI
    https://doi.org/10.7939/R31B0M
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.
  • Language
    English
  • Institution
    University of Alberta
  • Degree level
    Doctoral
  • Department
    • Department of Cell Biology
  • Supervisor / co-supervisor and their department(s)
    • Hobman, Tom (Department of Cell Biology)
  • Examining committee members and their departments
    • Campbell, Shelagh (Department of Biological Sciences)
    • Jan, Eric (Department of Biochemistry and Molecular Biology, University of British Columbia)
    • Fahlman, Richard (Department of Biochemistry)
    • Simmonds, Andrew (Department of Cell Biology)