Too Big to Function (image) Rockefeller University Share Print E-Mail Caption In this cross section of a kidney from a young FAN1 knockout mouse, cell nuclei are stained purple. Cells within a structure called the renal tubule exhibit karyomegaly, or enlarged nuclei. Credit The Laboratory of Genome Maintenance of The Rockefeller University/Genes and Development Usage Restrictions Image may be used only to illustrate the research described in the accompanying release. Share Print E-Mail 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.