Figure 1.

Recently born neurons may influence the fate of sister cells. Neural progenitors are polarised along the apico-basal axis of the neuroepithelium and localise apical polarity proteins such as Pard3 to the apical surface. Most neural progenitors divide at the apical surface of the neuroepithelium. A daughter that inherits the apical attachment (outlined by Pard3), inherits the Delta modulator Mindbomb and is likely to become a neuron. The daughter that transiently loses the apical attachment but retains the basal attachment is likely to remain a progenitor. Current evidence suggests that the neuronal daughter activates Notch signalling in its sister cell, promoting progenitor fate. However, exactly whether and when this occurs is not yet clear.