Dr. Toshio “Toshi” Tsukiyama studies how cells regulate chromatin, the packaging proteins responsible for compressing several feet of DNA inside each cell’s tiny nucleus. This genetic material needs to be carefully unpacked and repacked when cells need to divide or turn on genes at just the right time — two processes that can go wrong in cancer cells. Dr. Tsukiyama has discovered that a specific family of proteins helps the most basic units of chromatin — cartwheel-shaped molecular complexes around which DNA spools — slide along DNA to help control when genes are turned on and off. He also studies how the 3D structure of DNA, the large loops and folds it undergoes, can be harnessed to regulate cellular processes. Widespread gene shutdown and DNA compaction are hallmarks of an important, energy-conserving cellular state known as quiescence. Though quiescence is a normal state for cells in many of our tissues, it can also be used by cancer cells to resist chemotherapy. A deeper understanding of this state could lead to better treatments for cancer and other diseases. Dr. Tsukiyama studies how cells create the 3D DNA structure that helps them enter quiescence and keep genes turned off.