Numb and Numblike control cell number during vertebrate neurogenesis

A fundamental problem in nervous system development is how to control progenitor-cell divisions to generate the correct number of cells for the mature brain and spinal cord. A recent report by Petersen and colleagues has identified an essential role for Numb and a related protein, Numblike, in this process. This study demonstrates that Numb and Numblike function to maintain the self-renewal properties of neural progenitor cells in the vertebrate neural tube.