Fig. 6. Cas closes the third temporal identity window in the NB3-1 lineage. (A) Drosophila cas mutants have persistent Pdm expression in NB3-1 until at least mid stage 12 (M12); in wild type, Pdm is gone from NB3-1 by late stage 11 (see Fig. 1A). At mid stage 16, neuroblasts in the medial column no longer express Pdm (arrowheads); one of these neuroblasts is likely to be NB3-1. (B) In cas mutants, there are up to four ectopic Cut⁺ RP5 neurons; RP1, RP4 and RP3 are normal (Table 1). Wild type has RP1, RP4, RP3 and RP5 neurons (see Fig. 2). (C) cas misexpression (insc-gal4 UAS-cas) results in frequent loss of RP5 and occasional loss of RP3; RP1 and RP4 are normal (Table 1). For all panels, a single representative hemisegment of a stage-16 CNS is shown as a maximum intensity projection. Midline, left; anterior, up. A phenotype summary is shown to the right. Scale bars: 10 µm in A; 3 µm in B,C.