Fig. 4

Mapping OSN axon projections with recombineered BACs. a IRES:Gal4 was inserted just after the coding sequences of selected ORs and a heart-specific promoter driving fluorescent GFP was inserted at a second location distant from the co-labeled OR (see text and Methods for details). b Live confocal image from a double transgenic embryo in which or111–7 driven Gal4 activates UAS:Gap43-Citirine. A small number of OSNs are labeled with Citrine allowing the visualization of their cell bodies in the olfactory pits, axonal projections, and sites of termination in the olfactory bulb. c OSN projections in embryos from tgBACor111–7:IRES:Gal4x tgUAS:Citrine or tgBACor130–1:IRES:Gal4 x tgUAS:Citrine lines (left two columns). The same axonal projection patterns are observed in UAS:Citrine embryos transiently transfected with the BACs used to make the transgenic lines (right two columns). 3 dpf fixed embryos were co-stained with anti-GFP (green) and Propidium Iodide (Grey). The CZ (yellow), DZ (red), LG3 (blue), and MG (magenta) protoglomeruli are indicated on each single optical section. or111–7 expressing OSNs project to the CZ protoglomerulus, while or130–1 expressing OSNs project to the DZ protoglomerulus. Scale bar: 20 μm