Cells Expressing a Nuclear Marker (IMAGE) University of Colorado at Boulder Caption Cells expressing a nuclear marker (H2B) in cyan, a cell-cycle protein (Cyclin D1) in yellow and a proliferation marker (CDK2 activity sensor) in magenta. Credit Mingwei Min 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.