The Expanded Clock Gene Network (IMAGE) University of Pennsylvania School of Medicine Caption This is the Expanded Clock Gene Network. Clock components in the core feedback loop (blue), as well as other components known to regulate the clock (light blue), along with interacting genes (green, red, purple). Common interacting proteins are depicted in pink. Credit John Hogenesch, PhD, University of Pennsylvania School of Medicine; Cell Usage Restrictions None 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.