Let there be light and the process stops

The UVA-sensitive anhydrotetracycline can be used in cell cultures to regulate gene activities. (Photograph: Armin Baumschlager / ETH Zurich) - Researchers have discovered that they can use light-sensitive molecules to switch genetic networks on and off as required. Their finding gives rise to an easy method for dynamically controlling biotechnological substance production. Tetracycline (Tc), an antibiotic, and its derivative anhydrotetracycline (aTc) enjoy widespread use in biotechnology and synthetic biology. Both molecules influence gene expression. Tc generally inhibits the cellular machinery for the production of proteins, while aTc is used to activate specific genes. This is an indirect process in which aTc binds to a molecule attached to the corresponding gene and prevents it from being read by the cellular protein production machinery.