When genetically engineered to capture mRNA, vaults can store information about a cell’s past, much like a time capsule. Future experiments with vaults could potentially unlock treatments for cancer and other diseases by exposing a cell’s genetic record. They used a mysterious organelle known as a vault to store messenger RNA (mRNA), which kept a record of past cell activity. Recording could be turned on and off by adding or stopping the drug, which wore off within 24 hours if cell vaults were not regularly boosted with it. Chen is now using the vaults to find out more about how stem cells differentiate.