Figure 1: Engrailed+ V1 neurons project long, primarily ascending axons.
A. Transmitted light image (top) and confocal image (bottom) of a 5 dpf Tg (eng1b:Gal4,UAS:GFP) larva. In this and subsequent Figures, rostral is to the left and dorsal to the top. Some non-specific expression of GFP is present in muscle fibers as well. Scale bar: 0.5 mm B. Bar plot showing mean cell count of V1 neurons per segment along the rostro-caudal axis. n = 15 larvae from 4 clutches. Error bars represent SEM. C. Representative example of a sparsely labelled V1 neuron in a mid-body segment. Segment borders are shown in yellow dashed lines. Arrowheads mark the ascending axon, and the asterisk marks the descending axon. Scale bar: 20 μm. D. Ball and stick plots representing the soma (ball) and ascending and descending axon lengths of V1 neurons (sticks) relative to body segments. N = 28 neurons from 18 larvae. See also Figure S1.