Takumi Ishizuka, Kham Mo Aung, Baljinnyam Lkham-Erdene, Koichi Yano, Toshiki Kubota, Fidya, Shinichiro Shirouzu, Makoto Ikenoue, Kengo Kai, Phyu Synn Oo, Narantsog Choijookhuu, Yoshitaka Hishikawa
Guanine-rich DNA sequences can form four-stranded structures known as G-quadruplexes (G4s), which play important roles in cellular processes. However, direct observation of G4 dynamics in tissues remains challenging. Here, we report the in vivo dynamics of G4s during mouse liver regeneration after partial hepatectomy (PHx) using a G4-specific antibody. G4-positive hepatocytes gradually increased after PHx, peaking at 36 h, and then decreased, with signals predominantly in nuclei of cells in the peripheral region between the periportal and midzonal regions. Notably, double immunofluorescence analysis of cell cycle markers revealed that G4-positive cells colocalize with EdU- and Cyclin A2-positive cells, suggesting that G4 structures are formed during the S to G2 phases of the cell cycle. In mice deficient in high-mobility group box 2 (HMGB2), a candidate G4-interacting protein, G4-positive cells were significantly reduced compared with wild-type controls, although the temporal peak was preserved. Spatial distribution of G4-positive hepatocytes was also altered in Hmgb2−/− mice. This study provides the first evidence that G4-binding protein knockout mice can be used to assess the effects of these proteins on DNA G4 formation in vivo. © The Author(s) 2026.
Department of Anatomy, Histochemistry and Cell Biology, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki, 889-1692, Japan; Department of Thoracic Surgery, National Cancer Center of Mongolia, Nam Yan Ju street, Bayanzurkh District, Ulaanbaatar, 13370, Mongolia; Department of Surgery, Faculty of Medicine, University of Miyazaki, Miyazaki, 889-1692, Japan; Department of Oral and Maxillofacial Surgery, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki, 889-1692, Japan; Department of Oral Biology, Faculty of Dentistry, Universitas Brawijaya, Jawa Timur, Malang, 65145, Indonesia; Department of Pathology and Forensic Medicine, School of Biomedicine, Mongolian National University of Medical Sciences, Zorig street, Ulaanbaatar, 14120, Mongolia; Frontier Science Research Center, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki, 889-1692, Japan
