• Login
    View Item 
    •   Home
    • UMass Chan Student Research and Publications
    • Morningside Graduate School of Biomedical Sciences
    • Morningside Graduate School of Biomedical Sciences Dissertations and Theses
    • View Item
    •   Home
    • UMass Chan Student Research and Publications
    • Morningside Graduate School of Biomedical Sciences
    • Morningside Graduate School of Biomedical Sciences Dissertations and Theses
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Browse

    All of eScholarship@UMassChanCommunitiesPublication DateAuthorsUMass Chan AffiliationsTitlesDocument TypesKeywordsThis CollectionPublication DateAuthorsUMass Chan AffiliationsTitlesDocument TypesKeywords

    My Account

    LoginRegister

    Help

    AboutSubmission GuidelinesData Deposit PolicySearchingAccessibilityTerms of UseWebsite Migration FAQ

    Statistics

    Most Popular ItemsStatistics by CountryMost Popular Authors

    Biochemical Mechanism of Gene Expression Silencing by piRNA-directed PIWI-Clade Argonautes

    • CSV
    • RefMan
    • EndNote
    • BibTex
    • RefWorks
    Thumbnail
    Name:
    Arif_Amena_Final_Dissertation_ ...
    Embargo:
    2023-09-09
    Size:
    122.3Mb
    Format:
    PDF
    Download
    Authors
    Arif, Amena
    Faculty Advisor
    Phillip D. Zamore
    Academic Program
    Biochemistry and Molecular Pharmacology
    UMass Chan Affiliations
    RNA Therapeutics Institute
    Document Type
    Doctoral Dissertation
    Publication Date
    2021-08-10
    Keywords
    piRNA
    PIWI
    Argonaute
    Zinc-Finger
    GTSF1
    Spermatogenesis
    RNAi
    miRNAs
    siRNAs
    Asterix
    Evolution
    small RNA methylation
    non-coding RNAs
    small-silencing RNAs
    Biochemistry
    Biochemistry, Biophysics, and Structural Biology
    Molecular Biology
    Show allShow less
    
    Metadata
    Show full item record
    Abstract
    Argonaute proteins are small DNA/RNA-guided endonucleases found in all domains of life. In animals, small RNAs of length 21–35 nucleotides direct the PIWI-clade of Argonautes to silence complementary target RNAs; these are called PIWI-interacting RNAs (piRNAs). During spermatogenesis in mice, piRNA-guided PIWI proteins, MIWI2, MILI, and MIWI, silence transposons, regulate expression of protein-coding genes and are necessary for fertility. A working endonuclease activity of MIWI and MILI is essential to complete spermatogenesis. Yet, both MIWI and MILI produce weak and slow target cleavage in vitro, thwarting biochemical examination of the silencing step. Here, we find that PIWI proteins require an auxiliary protein to efficiently cleave their targets, unlike any other known Argonaute. Gametocyte Specific Factor 1 (GTSF1) is a conserved zinc-finger protein essential for fertility and piRNA-directed silencing. We show GTSF1 accelerates the pre-steady-state rate of target cleavage by MIWI and MILI; this role of GTSF1 is also preserved in insects. A critical step in GTSF1 mechanism entails binding RNA. GTSF1 allowed detailed kinetic analyses of catalytic PIWIs: they require extensive 3′ complementarity between the guide and target to efficiently cleave them, but this base-pairing also limits turnover. Interestingly, within a species, different PIWI proteins have unique kinetic properties. In sum, our findings provide molecular mechanisms of GTSF1 function and target silencing by PIWIs as well as a useful method for future studies.
    DOI
    10.13028/e70a-dc62
    Permanent Link to this Item
    http://hdl.handle.net/20.500.14038/31386
    Rights
    Copyright is held by the author, with all rights reserved.
    ae974a485f413a2113503eed53cd6c53
    10.13028/e70a-dc62
    Scopus Count
    Collections
    Morningside Graduate School of Biomedical Sciences Dissertations and Theses

    entitlement

     
    DSpace software (copyright © 2002 - 2023)  DuraSpace
    Lamar Soutter Library, UMass Chan Medical School | 55 Lake Avenue North | Worcester, MA 01655 USA
    Quick Guide | escholarship@umassmed.edu
    Open Repository is a service operated by 
    Atmire NV
     

    Export search results

    The export option will allow you to export the current search results of the entered query to a file. Different formats are available for download. To export the items, click on the button corresponding with the preferred download format.

    By default, clicking on the export buttons will result in a download of the allowed maximum amount of items.

    To select a subset of the search results, click "Selective Export" button and make a selection of the items you want to export. The amount of items that can be exported at once is similarly restricted as the full export.

    After making a selection, click one of the export format buttons. The amount of items that will be exported is indicated in the bubble next to export format.