Hydroxyurea ablation of mushroom bodies in Drosophila.

Chemical ablation is an effective tool for studying nervous system development and function in Drosophila. Hydroxyurea (HU) inhibits ribonucleotide reductase, blocking DNA synthesis, and killing dividing cells. The specificity of HU ablation is thus dependent on developmental events. In this respect, HU is useful in determining temporal patterns of neuroblast proliferation and the origins of neuronal elements in flies and other insects. In Drosophila, an especially fortuitous time window occurs at the end of embryonic development. For the first 8-12 h after larval hatching, only five neuroblasts are proliferating in each brain hemisphere. Four of these are found in the dorsal protocerebrum and give rise to the intrinsic elements (Kenyon cells [KCs] and glia) of the mushroom bodies (MBs). The remaining single neuroblast has an anterolateral position in the brain and is the progenitor of local interneurons (LocI) in the antennal lobe (AL) and a subset of lateral relay interneurons (RIl) in the inner antennocerebral tract (iACT). Treating newly hatched larvae with HU results in adult flies with KCs and AL interneurons of embryonic origin only. This protocol describes methods for collecting newly hatched Drosophila larvae and treating them with HU.