We did not detect significant colocalization with 5-HT, TH, or Ddc (data not shown). Thus, CG10251 is unlikely to store either dopamine or serotonin, in contrast to DVMAT, which localizes to these cell types (Greer et al., 2005). Other aminergic transmitters in the fly include octopamine and tyramine; however, DVMAT is likely responsible for their transport as well (Greer Selleck Cobimetinib et al., 2005), and both localize to large midline cells (Monastirioti et al., 1995 and Nagaya et al., 2002). We did not detect cells expressing CG10251 at the midline. In

the larval brain, we observed robust expression of CG10251 in the MBs (Figures 2D–2M). To confirm localization to cells in the MBs, we expressed mCD8-GFP with the MB driver 0K107-Gal4 ( Figures 2E and 2H; Connolly et al., 1996) and colabeled larval brains for CG10251 ( Figures 2D and GSI-IX price 2G). We observed overlap in the cell bodies of the KCs, their dendrites, which make up the

calyces, and their axons, which comprise the medial and vertical lobes of the MBs ( Figures 2D–2I). These data indicate that CG10251 is expressed by at least a subset of the KCs intrinsic to the MBs and therefore may be responsible for storage of neurotransmitter in these cells. In light of this expression pattern and the proposed transport function of CG10251, we have renamed the gene portabella (prt) and refer to the CG10251 protein as PRT. We note that subsets of KCs did not appear to be labeled (asterisks, Figure 2K) by the PRT antibody. A similar pattern has been reported for several developmental markers expressed in KCs (Noveen et al., 2000), suggesting that PRT may be expressed at a relatively late stage during differentiation and perhaps only in a subpopulation of KCs. We observed PRT expression in at least one bilateral extrinsic neuron projecting ipsilaterally to the vertical and medial lobes

of the larval MBs (arrowheads, Figures 2L and 2M). The location of and projections from this cell appear similar to that described for a neuron expressing the amnesiac peptide, which is critical for memory formation in Drosophila ( Waddell et al., 2000). However, colabeling experiments suggest that the extrinsic neurons expressing PRT are distinct from those expressing the amnesiac peptide ( Figure S2). Expression of PRT in these cells and four other small clusters in the larval brain is shown old schematically in Figure 2N. The Drosophila nervous system undergoes extensive remodeling during metamorphosis, resulting in adult MBs that are morphologically distinct from the larval structures. In the adult, each vertical lobe of the MB can be recognized as distinct α and α’ lobes, and the medial lobes include distinct β, β’, and γ lobes ( Crittenden et al., 1998). We observed strong PRT expression in the adult MBs, including labeling of all five lobes ( Figures 3A–3C). Relative to the lobes, labeling of the calyx and KC bodies was less intense in the adult than in the larva ( Figure 3E).