HUN-REN Research Centre for Natural Sciences 1 article published in JoVE Biology Visualizing Single-Stranded DNA Foci in the G1 Phase of the Cell Cycle Qingyue Zhang1,2, Marc A. Kerzhnerman1,2, Nelson García-Vázquez1,2,3, Gergely Rona1,2,4,5 1Department of Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, 2The Laura and Isaac Perlmutter Cancer Center, NYU Langone Health, 3Department of Cell Biology, NYU Grossman School of Medicine, 4Howard Hughes Medical Institute, NYU Grossman School of Medicine, 5Institute of Enzymology, Centre of Excellence of the Hungarian Academy of Sciences, HUN-REN Research Centre for Natural Sciences The following protocol presents the detection of single-stranded DNA foci in the G1 phase of the cell cycle utilizing cell cycle synchronization followed by RPA2 immunofluorescent staining.