Fig. 6. Fate of amos-expressing cells during olfactory development. (A-D,G) Activity of an amos SOP enhancer driving GFP expression. (A,B) At 8 hours APF, GFP can be detected in the third wave of olfactory precursors, some co-labelled SOPs are indicated by arrows (co-labelled with Sens and Amos in the separation in B). (C,D) The amos-GFP expressing cells contribute to late differentiating sensilla, as shown by lack of co-labelling with a neuronal marker (22C10) at 24 hours APF. C is a projection of many sections whereas D is a confocal section with some of the differentiating neurons marked by asterisks, these do not express GFP. (E,F) Later expression of amos does not correspond to PSC cells. (E) At 16 hours APF, Amos expression is fading, but there is no overlap with A101 ß-galactosidase expression in the PSCs, some of which are ringed. (F) There is no overlap of Amos expression with that of Pros, a marker of one of the PSCs. (G) amos-GFP construct at 30 hours APF: a large number of sensilla retain GFP. Protein appears to be in sensillar groups (as indicated by rings), and includes the outer support cells, so that sensilla trichodea (t) and basiconica (b) can clearly be discerned. (H,I) Analysis of amos-GFP in confocal sections of antennae at 24 hour APF relative to the component cells of the sensilla (see insets). n, neuron; sh, sheath; os, outer support cells. amos-GFP labels rows of cells corresponding to each sensillum basiconicum or trichodeum (some are ringed), whereas presumptive coeloconica (c) do not express GFP. (H) GFP is expressed in neurons (marked by Elav) and sheath cells (marked by Pros). (I) GFP is expressed in outer support cells (marked by stronger expression of Cut).