Wrinked vs. Smooth Nuclei (image) University of Pennsylvania Caption Cells grown on a soft matrix have a wrinkled nuclear lamina (green) -- but on stiff matrix, it is smoothed by high stress and stabilized, regulating gene expression. Credit Irena Ivanovska, University of Pennsylvania Usage Restrictions With Credit. 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.