Figure 9

The deutocerebral proliferative system in double pulse experiments (48-h interval between the pulses) with the S-phase markers BrdU (first pulse, red) and EdU (second pulse, green) combined with immunolocalization of tyrosinated tubulin (white); POI stage. (A) In the cap most cycling cells have incorporated both labels. One exception is shown in the inset in (B), where one cell only has incorporated the first label (arrowheads in the inset). Note that compared to the cap, very few cells are in S-phase in the core (arrows in A and B). (C, D) Cluster 10 (dotted line) and lateral proliferation zone (LPZ) are shown. A mix of dividing cells and progeny is present. Panel ( D) shows the same specimen as (C) but is focused deeper into the tissue. The green dashed line encircles a zone in which only cells with the first label are present. These may be postmitotic cells that are on their way to differentiation and being integrated into cluster 10. (E) Stars identify two large nuclei that have incorporated both labels and hence were actively cycling during the second pulse. The white arrows identify smaller cells. Most of these have only the first label but one of these intermediate cells has both labels. The white arrowheads identify two cells that may represent two telophases. (F) Overview of the deutocerebral proliferative system. Note the strong mitotic activity in the LPZ and the cap. Abbreviations: LPZ, lateral proliferative zone; GN, medial giant neuron. Scale bars: 20 μm (A, B, C), 10 μm (E); 50 μm (F)..