A requirement for Notch in the genesis of a subset of glial cells in the Drosophila embryonic central nervous system which arise through asymmetric divisions

In the Drosophila central nervous system (CNS) glial cells are known to be generated from glioblasts, which produce exclusively glia or neuroglioblast s that bifurcate to produce both neuronal and glial sublineages. We show th at the genesis of a subset of glial cells, the subperineurial glia (SPGs), involves a new mechanism and requires Notch. We demonstrate that the SPGs s hare direct sibling relationships with neurones and are the products of asy mmetric divisions. This mechanism of specifying glial cell fates within the CNS is novel and provides further insight into regulatory interactions lea ding to glial cell fate determination. Furthermore, we show that Notch sign alling positively regulates glial cells missing (gcm) expression in the con text of SPG development.