Fig. 2. Sequential expression of temporal transcription factors in NB3-3T and NB3-3A. The Drosophila NB3-3T and NB3-3A lineages were visualized using Eg, eg>GFP or eg>LacZ (green). White arrowheads indicate NB3-3. (A,B) Kr, Pdm, Cas, Svp and Grh expression (magenta) in NB3-3T (A) and NB3-3A (B) during embryogenesis. (C) NB3-3T lineage from wild-type larva at 20-25 hours ALH (0 progeny, left) and 25-30 hours ALH (1 progeny, right) continuously labeled with BrdU from hatching. Cas expression and BrdU incorporation are shown in magenta. Yellow arrowhead indicates the first NB3-3T larval progeny. (D) Cas and Svp expression and BrdU incorporation (magenta) in larval NB3-3T at the indicated time (ALH). (E) Schematic of the quiescence period in NB3-3T and expression of the temporal transcription factors in NB3-3T (upper) and NB3-3A (lower). (F) Schematic model of NB3-3 lineage development. Expression patterns of the temporal factors are shown by the indicated color. EL neurons are enclosed by gray rectangles. The late Cas expression was downregulated without Svp function (data not shown).