hDNA2 nuclease/helicase promotes centromeric DNA replication and genome stability

• Published in: The EMBO journal Vol. 37; no. 14
• Main Authors: Li, Zhengke, Liu, Bochao, Jin, Weiwei, Wu, Xiwei, Zhou, Mian, Liu, Vincent Zewen, Goel, Ajay, Shen, Zhiyuan, Zheng, Li, Shen, Binghui
• Format: Journal Article
• Language: English
• Published: England Blackwell Publishing Ltd 13.07.2018; John Wiley and Sons Inc
• Subjects: Activation; Cancer; Cell Cycle; cell cycle arrest; Cell Line; centromere; Centromere - metabolism; Centromeres; centromeric DNA replication; chromosome segregation; Chromosomes; Chromosomes, Human - metabolism; Deoxyribonucleic acid; Deposition; DNA; DNA biosynthesis; DNA damage; DNA helicase; DNA Helicases - deficiency; DNA Helicases - metabolism; DNA Replication; DNA2; Eukaryotes; Genomes; Genomic Instability; Humans; Inhibitors; Metaphase; Nuclease; Plates (structural members); Replication; centromere; DNA2; chromosome segregation; cell cycle arrest; centromeric DNA replication
• DOI: 10.15252/embj.201796729
• ISSN: 0261-4189

DNA2 is a nuclease/helicase that is involved in Okazaki fragment maturation, replication fork processing, and end resection of DNA double‐strand breaks. Similar such helicase activity for resolving secondary structures and structure‐specific nuclease activity are needed during DNA replication to process the chromosome‐specific higher order repeat units present in the centromeres of human chromosomes. Here, we show that DNA2 binds preferentially to centromeric DNA. The nuclease and helicase activities of DNA2 are both essential for resolution of DNA structural obstacles to facilitate DNA replication fork movement. Loss of DNA2‐mediated clean‐up mechanisms impairs centromeric DNA replication and CENP‐A deposition, leading to activation of the ATR DNA damage checkpoints at centromeric DNA regions and late‐S/G2 cell cycle arrest. Cells that escape arrest show impaired metaphase plate formation and abnormal chromosomal segregation. Furthermore, the DNA2 inhibitor C5 mimics DNA2 knockout and synergistically kills cancer cells when combined with an ATR inhibitor. These findings provide mechanistic insights into how DNA2 supports replication of centromeric DNA and give further insights into new therapeutic strategies. Synopsis Whole genome screening uncovers an essential role of DNA2 helicase/nuclease, known to be involved in replication fork processing and double‐strand break resection, in resolution of DNA secondary structures arising during replication of centromeric repeat DNA. Human DNA2 is specifically recruited to centromeric DNA regions of the genome. The nuclease and helicase activities of DNA2 are both essential for resolution of DNA structural obstacles to facilitate replication fork movement. Loss of DNA2‐mediated clean‐up mechanisms impairs centromeric replication and causes defects in CENP‐A deposition, leading to ATR checkpoint activation and late‐S/G2 cell cycle arrest. Combined application of the DNA2 and ATR inhibitors synergistically kills cancer cells and may offer new therapeutic strategies. Whole genome screening uncovers an essential role of DNA2 helicase/nuclease in resolution of DNA secondary structures to facilitate replication of centromeric repeat DNA.