Viruses depend on host cells for replication, but how does a virus induce its host to transcribe its own genetic information alongside that of the virus, thus producing daughter viruses? For decades, researchers have been studying a type of bacteriophage known as lambda to try and find an answer to this question. Using high-resolution cryo-electron microscopy, a research group from Charité – Universitätsmedizin Berlin has now successfully deciphered this process. Their findings have been published in Molecular Cell.