Sanford, Samantha
(2021)
Mechanisms of telomerase inhibition by oxidized and therapeutic dNTPs.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
This is the latest version of this item.
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.
Share
| Citation/Export: |
|
| Social Networking: |
|
Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
|
| Date: |
19 January 2021 |
| Date Type: |
Publication |
| Defense Date: |
12 August 2020 |
| Approval Date: |
19 January 2021 |
| Submission Date: |
12 November 2020 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Number of Pages: |
190 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
School of Public Health > Infectious Diseases and Microbiology |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
telomeres, telomerase |
| Date Deposited: |
19 Jan 2021 20:50 |
| Last Modified: |
19 Jan 2021 20:50 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/39981 |
Available Versions of this Item
-
Mechanisms of telomerase inhibition by oxidized and therapeutic dNTPs. (deposited 19 Jan 2021 20:50)
[Currently Displayed]
Metrics
Monthly Views for the past 3 years
Plum Analytics
Actions (login required)
 |
View Item |
![[feed]](/images/feed-icon-32x32.png){kind=icon}