Fig. 7. Requirements for prospero in separating glial and neuronal cell fates. In wild type, low level gcm mRNA and protein (gray) are evenly segregated to the NGB and the daughter cell. The daughter cell inherits all Prospero, which upregulates gcm expression and induces glial fate (black). In prospero mutants, low level gcm expression (gray) is induced normally in the NGB but fades rapidly and glia are not produced. In miranda mutants, Prospero is evenly segregated into the NGB and the daughter cell resulting in either (1) upregulation of gcm in the NGB, its transformation into a GB or glial cell, and the truncation of the lineage (black); or (2) insufficient Prospero is present in the NGB, low level gcm fades in the NGB, and neuronal progeny are subsequently produced (NB, white).