Kidney Development (IMAGE) Washington University School of Medicine Caption The image on the right shows a normal mouse kidney at a very early stage of development. The green staining marks the stem cells. The pink staining shows the early daughter cells taking the first steps toward becoming adult nephrons. The image on the left shows a mouse kidney at the same early developmental stage, but without both FGF9 and FGF20. Without these two proteins maintaining the stem cell niche, all the green stem cells differentiate to pink daughter cells right away. The pool of stem cells is exhausted and there is no further kidney growth. Credit Hila Barak, Ph.D. 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.