Let There be Light (IMAGE) University of Basel Caption An artificial metalloenzyme (blue) penetrates a mammalian cell, where it accelerates the release of a hormone (blue to red spheres). This activates a gene switch (circles with arrowheads), which then leads to the production of a fluorescent indicator protein (light green glow around the cell). Credit University of Basel, Yasunori Okamoto Usage Restrictions give adequate attribution to original author License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.