Mouse Egg Cells (IMAGE) Kyushu University Caption The egg cells in this reconstituted mouse ovary created from embryonic stem cells were treated to appear green. Researchers from Kyushu University obtained dormant egg cells, which are much smaller than the larger, growing egg cells, by limiting the oxygen and increasing the amount of the protein FOXO3. Without such conditions, the egg cells created in the lab quickly pass through the dormant state and mature. Credit So Shimamoto, Kyushu University Usage Restrictions Only for media and non-commercial use. 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.