eprintid: 39981
rev_number: 12
userid: 3867
dir: disk0/00/03/99/81
datestamp: 2021-01-19 20:50:25
lastmod: 2021-01-19 20:50:25
status_changed: 2021-01-19 20:50:25
type: thesis_degree
succeeds: 39879
metadata_visibility: show
contact_email: sas354@pitt.edu
item_issues_id: duplicate_title_39935
item_issues_id: thesis_degree_versioning
item_issues_id: duplicate_title_39879
item_issues_type: duplicate_title
item_issues_type: thesis_degree_versioning
item_issues_type: duplicate_title
item_issues_description: Duplicate title to 


    <span class="person_name">Sanford, Samantha</span>
  



<a href="http://d-scholarship.pitt.edu/cgi/users/home?screen=EPrint::View&amp;eprintid=39935"><xhtml:em xmlns:xhtml="http://www.w3.org/1999/xhtml">Mechanisms of telomerase inhibition by oxidized and therapeutic dNTPs.</xhtml:em></a>


    Doctoral Dissertation, University of Pittsburgh.
  


   (Unpublished)
item_issues_description: ETD 39981 is using versioning.
item_issues_description: Duplicate title to 


    <span class="person_name">Sanford, Samantha</span>
  



<a href="http://d-scholarship.pitt.edu/cgi/users/home?screen=EPrint::View&amp;eprintid=39879"><xhtml:em xmlns:xhtml="http://www.w3.org/1999/xhtml">Mechanisms of telomerase inhibition by oxidized and therapeutic dNTPs.</xhtml:em></a>


    Doctoral Dissertation, University of Pittsburgh.
  


   (Unpublished)
item_issues_timestamp: 2020-11-25 07:02:25
item_issues_timestamp: 2021-01-06 07:02:30
item_issues_timestamp: 2021-01-06 07:02:30
item_issues_status: autoresolved
item_issues_status: discovered
item_issues_status: autoresolved
item_issues_count: 1
eprint_status: archive
creators_name: Sanford, Samantha
creators_email: sas354@pitt.edu
creators_id: sas354
title: Mechanisms of telomerase inhibition by oxidized and therapeutic dNTPs
ispublished: unpub
divisions: sch_gsph_infectiousdiseasesmicrobiology
full_text_status: public
keywords: telomeres, telomerase
abstract: Telomeres cap chromosome ends and are essential for genome stability and human health, but they shorten in most human somatic cells with cell division due to the end replication problem. Telomerase a specialized reverse transcriptase that lengthens telomeres by adding GGTTAG repeats to chromosome ends and is upregulated in most human cancers to enable limitless proliferation. Here, we uncover two distinct mechanisms by which naturally occurring oxidized and therapeutic dNTP DNA precursors inhibit telomerase-mediated telomere elongation. We conducted a series of direct telomerase extension assays in the presence of modified dNTPs on various telomeric substrates. We provide direct evidence that telomerase can add the metabolized form of NRTIs, dideoxyadenosine 5’ triphosphate (ddITP) and 3’-azido-3’deoxythymidine triphosphate (AZT-TP), to the telomeric end, causing chain termination. In contrast, telomerase continues elongation after inserting oxidized 2-OH-dATP or the therapeutic 6-thioguanine metabolite, 6-thio-dGTP, but insertion disrupts translocation and inhibits further repeat addition. Kinetics reveal that telomerase poorly selects against 6-thio-dGTP, inserting with similar catalytic efficiency as dGTP. Furthermore, telomerase processivity factor POT1-TPP1 fails to restore processive elongation in the presence of inhibitory dNTPs. These findings reveal mechanisms for targeting telomerase with modified dNTPs in cancer therapy.
date: 2021-01-19
date_type: published
pages: 190
institution: University of Pittsburgh
refereed: TRUE
etdcommittee_type: committee_chair
etdcommittee_type: committee_cochair
etdcommittee_type: committee_member
etdcommittee_type: committee_member
etdcommittee_type: committee_member
etdcommittee_name: Opresko, Patricia
etdcommittee_name: Ayyavoo, Velpandi
etdcommittee_name: Van Houten, Bennett
etdcommittee_name: Berman, Andrea
etdcommittee_name: Martinson, Jeremy
etdcommittee_email: plo4@pitt.edu
etdcommittee_email: velpandi@pitt.edu
etdcommittee_email: vanhoutenb@upmc.edu
etdcommittee_email: ajb190@pitt.edu
etdcommittee_email: jmartins@pitt.edu
etdcommittee_id: plo4
etdcommittee_id: velpandi
etdcommittee_id: vanhoutenb
etdcommittee_id: ajb190
etdcommittee_id: jmartins
etd_defense_date: 2020-08-12
etd_approval_date: 2021-01-19
etd_submission_date: 2020-11-12
etd_release_date: 2021-01-19
etd_access_restriction: immediate
etd_patent_pending: FALSE
thesis_type: dissertation
degree: PhD
citation:   Sanford, Samantha  (2021) Mechanisms of telomerase inhibition by oxidized and therapeutic dNTPs.  Doctoral Dissertation, University of Pittsburgh.    (Unpublished)  
document_url: http://d-scholarship-dev.library.pitt.edu/39981/7/ssanford%20dissertation%20final%2012%2017%2020.pdf