Dr. Yasuhiro Arimura studies chromatin, the mixture of DNA and DNA-packaging proteins. Chromatin is “marked” with numerous chemical or structural cues that enable cells to organize DNA and manage how (and when) genes are turned on and off. These marks also help ensure that dividing cells properly sort their chromosomes. Cancer cells often have an unusual number of chromosomes — a sign that the molecular marks on their chromatin are not working as they should. Dr. Arimura works to understand the roles that the molecular cues play in various chromatin-dependent cellular processes. He developed an innovative method to extract chromatin with a specific mark and uses a specialized type of microscopy, called cryogenic electron microscopy (or cryo-EM) to visualize it. Dr. Arimura’s insights will help scientists better understand how chromatin functions, how it’s regulated, and what goes wrong in diseases like cancer.