Figure 4.

Aberrant Eya expression reveals different categories of mutants. (A and B) In wild type, Eya is expressed in the Ap cluster neurons in each thoracic hemi-segment, as well as in the two rows of dAp neurons. (C) One category of mutants, exemplified by Pcl^03P002, displayed loss of Eya expression in Ap clusters, but unaffected Eya expression in the dAp neurons. (D) Another category, exemplified by mira^11A017, displayed loss of Eya expression in the entire VNC. (E–G) Examples of mutants with additional Eya expression either in organized stripes (E and F) or in “clumps” (G). (H–P) Staining with antibodies to proFMRFa, Eya, and pMad further categorized mutants regarding Ap cluster specification and BMP/TGFb signaling. (H, K, and N) In wild type, FMRFa is expressed in the six Ap4/FMRFa cells in the ventral nerve cord and in the two SE2 cells the brain. Eya is expressed in the Ap neurons in each thoracic hemi-segment and in the dAp neurons. pMad is found throughout the VNC in motor neurons and susbsets of neuropeptide neurons, among them the Ap4/FMRFa neurons (Allan et al. 2003; Marques et al. 2003). (I, L, and O) The col^05FT mutant shows no endogenous FMRFa expression in Ap cells, while expression in SE2 cells is unaffected. Eya expression is lost in the entire VNC, while pMad staining is unaffected. (J, M, and P) In the gbb^03F122 mutant, FMRFa expression is lost in the Ap4 neurons but maintained in the SE2 cells. Eya is expressed in both the Ap clusters and the dAp neurons, while pMad is lost from the entire VNC.