Fig. 3. Dachshund and Eyes Absent are expressed in subsets of peptidergic neurons. (A) Expression of dac (dac^GAL4/UAS-myc-EGFP^F) is observed in subsets of neurons in the embryonic VNC, including a lateral cluster of cells in the three thoracic segments (arrows). (B-L) Expression of Dac and Eya in late-stage-17 embryos. (B,B',B'') Expression of Dac and the glia-specific marker repo (repo^GAL4/UAS-nls-myc-EGFP) reveals that Dac is not expressed in glia. (C,C',C'') Expression of Dac and pMad reveals that Dac is not expressed in motoneurons. Expression of Dac is evident in the pCC interneuron (arrow in C) and in the Va peptidergic cells (arrowheads in C''). (D) From embryonic stage 16, expression of Eya is observed in a highly restricted set of cells in the VNC. (E) Expression of Dac (red), Fmrf (blue) and ap (ap^GAL4/UAS-nls-myc-EGFP; green) shows that Dac is expressed in three of the four ap-cluster cells, including the Tv cell (arrow), but is absent from the dAp cell (arrowhead). (F) Expression of Eya (red), Fmrf (blue) and ap (ap^GAL4/UAS-nls-myc-EGFP; green) shows that Eya is expressed in all four ap-cluster cells, including the Tv cell (arrow) and in the dAp cell (arrowhead). (G,H) c929-GAL4 and Fmrf-lacZ co-labeling discriminates the Tv cell (c929-GAL4+, Fmrf-lacZ+) and the Tvb and the dAp cells (c929-GAL4+, Fmrf-lacZ-negative). (G) Expression of Dac (red), Fmrf (blue) and c929-GAL4/UAS-nls-myc-EGFP (green) shows that Dac is not expressed in the Tvb neuron (arrow) or the dAp cell (arrowhead). (H) Expression of Eya (red), Fmrf (blue) and c929-GAL4/UAS-nls-myc-EGFP (green) shows that Eya is expressed in both the Tvb neuron (arrow) and dAp cell (arrowhead). (I-L) Expression of Dac and c929-GAL4/UAS-nls-myc-EGFP shows that Dac is expressed in Va neurons (arrow in I) and posterior dMP2 neurons (arrow in J), is absent from corazonin neurons (arrowhead in K), present in the Vi neurons (arrow in L) and absent from the Plc neurons (arrowhead in L). The dMP2 neurons were previously described as Vap neurons (Allan et al., 2003). However, subsequent work has revealed that Vap neurons are, in fact, the well-characterized dMP2 neurons (I.M-A. and S.T., unpublished). (M) Summary of the expression of Ap, Dac, Eya and pMad within peptidergic neurons of the stage-17 embryonic and larval Drosophila VNC. Note that either Dac or Eya are expressed in all peptidergic neurons that express Fmrf in response to the ap/sqz/BMP code.