• 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

    Understanding Small RNA Formation in Drosophila Melanogaster: A Dissertation

    • CSV
    • RefMan
    • EndNote
    • BibTex
    • RefWorks
    Thumbnail
    Name:
    Cenik_ElifSarinay_reduced.pdf
    Size:
    5.316Mb
    Format:
    PDF
    Download
    Authors
    Cenik, Elif Sarinay
    Faculty Advisor
    Phillip D. Zamore, Ph.D.
    Academic Program
    Biochemistry and Molecular Pharmacology
    UMass Chan Affiliations
    RNA Therapeutics Institute
    Document Type
    Doctoral Dissertation
    Publication Date
    2012-07-09
    Keywords
    Drosophila Proteins
    RNA
    Small Interfering
    MicroRNAs
    RNA Helicases
    Ribonuclease III
    Substrate Specificity
    Amino Acids, Peptides, and Proteins
    Animal Experimentation and Research
    Biochemistry, Biophysics, and Structural Biology
    Enzymes and Coenzymes
    Nucleic Acids, Nucleotides, and Nucleosides
    Show allShow less
    
    Metadata
    Show full item record
    Abstract
    Drosophila Dicer-2 generates small interfering RNAs (siRNAs) from long double-stranded RNA (dsRNA), whereas Dicer-1 produces microRNAs from premicroRNA. My thesis focuses on the functional characteristics of two Drosophila Dicers that makes them specific for their biological substrates. We found that RNA binding protein partners of Dicers and two small molecules, ATP and phosphate are key in regulating Drosophila Dicers’ specificity. Without any additional factor, recombinant Dicer-2 cleaves pre-miRNA, but its product is shorter than the authentic miRNA. However, the protein R2D2 and inorganic phosphate block pre-miRNA processing by Dicer-2. In contrast, Dicer-1 is inherently capable of processing the substrates of Dicer, long dsRNAs. Yet, partner protein of Dicer-1, Loqs-PB and ATP increase the efficiency of miRNA production from pre-miRNAs by Dicer-1, therefore enhance substrate specificity of Dicer-1. Our data highlight the role of ATP and regulatory dsRNA-binding partner proteins to achieve substrate specificity in Drosophila RNA silencing. Our study also sheds light onto the function of the helicase domain in Drosophila Dicers. Although Dicer-1 doesn’t hydrolyze ATP, ATP enhances miRNA production by increasing Dicer-1’s substrate specificity through lowering its KM. On the other hand, Dicer-2 is a dsRNA-stimulated ATPase that hydrolyzes ATP to ADP, and ATP hydrolysis is required for Dicer-2 to process long dsRNA. Wild-type Dicer-2, but not a mutant defective in ATP hydrolysis, is processive; generating siRNAs faster than it can dissociate from a long dsRNA substrate. We propose that the Dicer-2 helicase domain uses ATP to generate many siRNAs from a single molecule of dsRNA before dissociating from its substrate. Piwi-dependent small RNAs, namely piRNAs, are a third class of small RNAs that are distinct from miRNAs and siRNAs. Their primary function is to repress transposons in the animal germline. piRNAs are Dicer-independent, and require Piwi family proteins for their biogenesis and function. Recently in addition to their presence in animal germlines, the presence and function of piRNA-like RNAs in the somatic tissues have been suggested (Yan et al. 2011; Morazzani et al. 2012; Rajasethupathy et al. 2012). We have investigated whether the piRNA-like reads in our many Drosophila head libraries come from the germline as a contaminant or are soma-specific. Most of the piRNA reads in our published head libraries show high similarity to germline piRNAs. However, piRNA-like reads from manually dissected heads are distinct from germline piRNAs, proving the presence of somatic piRNA-like small RNAs. We are currently asking the question whether these distinct piRNA-like reads in the heads are dependent on the Piwi family proteins, like the germline piRNAs.
    DOI
    10.13028/bw3j-x330
    Permanent Link to this Item
    http://hdl.handle.net/20.500.14038/31963
    Rights
    Copyright is held by the author, with all rights reserved.
    ae974a485f413a2113503eed53cd6c53
    10.13028/bw3j-x330
    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.