Ava Siegel1, Daniel Almstead2, Lindsay Allen2, Erica Lamkin2, Naveen Kothandaraman2, Kanayo Ikeh2, Hannah Koval3, Andrew Crompton2, Jessica Reich2, Roxana Del Rio Guerra3, Dmitry Korzhnev4, Kyle Hadden4, Jiyong Hong5, Pei Zhou6, Nimrat Chatterjee2
1Larner College of Medicine, 2Department of Microbiology and Molecular Genetics, University of Vermont, 3University of Vermont Cancer Center, 4Department of Pharmaceutical Sciences, University of Connecticut, 5Department of Chemistry, 6Department of Biochemistry, Duke University
Objective:
To explore the role of the translesion synthesis (TLS) polymerase REV1 in trinucleotide repeat (TNR) instability mechanisms.
Background:
The expansion and contraction of unstable trinucleotide repeat (TNR) regions in DNA is the physiologic basis behind numerous neurologic disorders. Drivers of TNR instability center around DNA replication and repair pathways, with recent studies investigating the role of TLS polymerases in TNR instability. These polymerases allow cells to replicate through existing DNA damage or repetitive DNA-induced secondary structures, generating new mutations or repeat length alterations, respectively. Recent evidence has also identified rereplication as a mechanism for TNR mutagenesis.
Design/Methods:
To investigate the relationship between REV1 and TNR instability, we used a human cell line model containing a quantitative GFP reporter of TNR instability. We employed REV1 inhibitors to limit REV1 and recovery from aphidicolin as a tool to create rereplication.
Results:
REV1 inhibition generally increased TNR instability, suggesting that REV1 is required to replicate through potential secondary structures, and its absence causes replication collapse and TNR instability. However, preliminary data suggests that REV1-inhibited cells exhibited reduced rereplication-dependent TNR instability, possibly due to REV1’s requirement to also replicate through rereplication-induced secondary structures.
Conclusions:
Our study unveils the pivotal role of REV1 in TNR instability, particularly in its capacity to replicate through secondary structures. Its absence leads to escalated TNR instability. Moreover, REV1’s participation in replication at these repeats is confirmed, as their collapse is more likely due to the lack of continued and necessary replication at repeat secondary structures. By inducing DNA rereplication, another catalyst of TNR instability, we demonstrate that REV1 is indispensable for this process. Understanding the role of TLS in TNR instability has profound implications for the field of genetics and molecular biology, offering insights into mechanisms behind TNR mutagenesis and its contribution to disease pathology.
Disclaimer: Abstracts were not reviewed by Neurology® and do not reflect the views of Neurology® editors or staff.