Research Paper|Volume 15, Issue 19|pp 10767—10784

Modified iPOND revealed the role of mutant p53 in promoting helicase function and telomere maintenance

Qianqian Wang¹, Kailong Hou², Jun Yang¹, Haili Li³, Cui Li⁴, Yanduo Zhang², Jie Tian¹, Chuanbiao Li¹, Bing Guo¹, Shuting Jia², Ying Luo¹

¹Department of Pathophysiology, School of Basic Medicine, Guizhou Medical University, Guiyang 550025, Guizhou, China
²Lab of Molecular Genetics of Aging and Tumor, Medical School, Kunming University of Science and Technology, Kunming 650500, Yunnan Province, China
³Department of Human Anatomy, School of Basic Medicine, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan 250117, Shandong, China
⁴Institute of Molecular Physiology, Shenzhen Bay Laboratory, Shenzhen 518132, Guangdong, China

Received: February 11, 2023Accepted: September 25, 2023Published: October 12, 2023

https://doi.org/10.18632/aging.205117

Copyright: © 2023 Wang et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Abstract

The G-rich DNA, such as telomere, tends to form G-quadruplex (G4) structure, which slows down the replication fork progression, induces replication stress, and becomes the chromosome fragile sites. Here we described a molecular strategy that cells developed to overcome the DNA replication stress via DNA helicase regulation.

The p53N236S (p53S) mutation has been found in the Werner syndrome mouse embryo fibroblast (MEFs) escaped from senescence, could be the driving force for cell escaping senescence. We revealed that the p53S could transcriptionally up-regulate DNA helicases expression, including Wrn, Blm, Timeless, Ddx, Mcm, Gins, Fanc, as well as telomere specific proteins Terf1, Pot1, through which p53S promoted the unwinding of G4 structures, and protected the cells from DNA replication stress induced by G4 stabilizer. By modified iPOND (isolation of proteins on nascent DNA) assay and telomere assay, we demonstrated that the p53S could promote the recruitment of those helicases to the DNA replication forks, facilitated the maintenance of telomere, and prevent the telomere dysfunction induced by G4 stabilizer. Interestingly, we did not observe the function of promoting G4 resolving and facilitating telomere lengthening in the cells with Li-Fraumeni Syndrome mutation-p53R172H (p53H), which suggests that this is the specific gain of function for p53S.

Together our data suggest that the p53S could gain the new function of releasing the replication stress via regulating the helicase function and G4 structure, which benefits telomere lengthening. This strategy could be applied to the treatment of diseases caused by telomere replication stress.