Sequential expression of temporal transcription factors within neuroblasts in the <i>Drosophila</i> CNS.

<p>(<b>A</b>) The relative position of neuroblasts (NBs) in <i>Drosophila</i> embryo. The picture is the ventral view of NBs and shows Cas expression in the NBs at developmental stage 12. The bracket indicates a single segment. Dashed line corresponds to the midline. Scale bar: . (<b>B</b>) The expression levels of Hb, Kr, Pdm, and Cas in a single NB (NB 2–4 lineage) are shown from the developmental stage 10 to 12: early stage 10 (st. 10), early stage 11 (e11), mid stage 11 (11), late stage 11 (l11), mid stage 12 (12), late stage 12 (l12). (<b>C</b>) Schematic representation of the change of the expression pattern in a single NB. (<b>D</b>) The expression profiles of WT, loss-of-function, and overexpression mutants of the genes observed in the experiments (for references, see <a href="" target="_blank">Table 2</a>). (<b>E</b>) Reconstructed genetic network for sequential expression in <i>Drosophila</i> NBs. Repression from <i>hb</i> to <i>cas</i> (dashed line) was suggested to exist <a href="" target="_blank">[26]</a>, although there is no direct verification. When the <i>Drosophila</i> network is invoked in this article, this regulation is also included. (<b>F</b>) Matrix representation of the <i>Drosophila</i> network.</p>