TY - BOOK

T1 - The Role of ZGRF1 in Recombinational Repair and Telomere Stability Maintenance

AU - Bagge, Keerthana Stine Viswalingam

PY - 2023

Y1 - 2023

N2 - Genome stability is important to maintain cellular survival. It can be challenged by the accumulation of DNA damage that may be inadequately repaired, causing genomic instability. In this study we characterize a human helicase, ZGRF1, and its role in DNA repair. We previously reported that ZGRF1 promotes recombinational repair at replication-blocking DNA lesions and showed that ZGRF1-deficient cells are sensitivity to the interstrand crosslinking agent, Mitomycin C (MMC), causing elevated levels of chromosomal aberrations. Interstrand crosslinks (ICLs) are repaired by the replication-dependent Fanconi anemia (FA) pathway, and we showed that ZGRF1 colocalizes with the FANCD2, which is an important protein in the FA pathway. To extend the characterization of ZGRF1 in ICL-repair, we analyzed the spatio-temporal recruitment of ZGRF1 and FANCD2 foci by live-cell time-lapse microscopy. Additionally, we demonstrate that ZGRF1 focus formation depends on BRCA2, the Rad51 stabilizing protein, supporting our previous finding that ZGRF1 stimulates Rad51-mediated strand-exchange. To identify yet unknown roles of ZGRF1, we performed an unbiased genome-wide CRISPR knockout screen and identified a putative telomere-related role of ZGRF1. Additionally, this screen contributed to the identification of SCAI as a novel player in the FA pathway. Telomeres are genomic regions at the chromosome ends that are highly enriched in replication-blocking lesions. Several DNA repair proteins are also associated with telomere maintenance, and in fact, ZGRF1 also localizes to telomeres. Interestingly, ZGRF1-depleted cells display longer telomeres and ZGRF1 evidently promotes the ATM-mediated DNA damage response at deprotected telomere. In summary, we further characterize the role of ZGRF1 in ICL repair, by its role in homologous recombination (HR) and propose at new role of ZGRF1 in telomere stability maintenance.

AB - Genome stability is important to maintain cellular survival. It can be challenged by the accumulation of DNA damage that may be inadequately repaired, causing genomic instability. In this study we characterize a human helicase, ZGRF1, and its role in DNA repair. We previously reported that ZGRF1 promotes recombinational repair at replication-blocking DNA lesions and showed that ZGRF1-deficient cells are sensitivity to the interstrand crosslinking agent, Mitomycin C (MMC), causing elevated levels of chromosomal aberrations. Interstrand crosslinks (ICLs) are repaired by the replication-dependent Fanconi anemia (FA) pathway, and we showed that ZGRF1 colocalizes with the FANCD2, which is an important protein in the FA pathway. To extend the characterization of ZGRF1 in ICL-repair, we analyzed the spatio-temporal recruitment of ZGRF1 and FANCD2 foci by live-cell time-lapse microscopy. Additionally, we demonstrate that ZGRF1 focus formation depends on BRCA2, the Rad51 stabilizing protein, supporting our previous finding that ZGRF1 stimulates Rad51-mediated strand-exchange. To identify yet unknown roles of ZGRF1, we performed an unbiased genome-wide CRISPR knockout screen and identified a putative telomere-related role of ZGRF1. Additionally, this screen contributed to the identification of SCAI as a novel player in the FA pathway. Telomeres are genomic regions at the chromosome ends that are highly enriched in replication-blocking lesions. Several DNA repair proteins are also associated with telomere maintenance, and in fact, ZGRF1 also localizes to telomeres. Interestingly, ZGRF1-depleted cells display longer telomeres and ZGRF1 evidently promotes the ATM-mediated DNA damage response at deprotected telomere. In summary, we further characterize the role of ZGRF1 in ICL repair, by its role in homologous recombination (HR) and propose at new role of ZGRF1 in telomere stability maintenance.

M3 - Ph.D. thesis

BT - The Role of ZGRF1 in Recombinational Repair and Telomere Stability Maintenance

PB - Department of Biology, Faculty of Science, University of Copenhagen

ER -