A mutated Or42a promoter can drive expression in multiple chemosensory neurons in the larvae.

(A) Confocal micrograph Z-projections of olfactory neurons with dendrites innervating the Dome sensillum seen as fluorescent dome structure called the Dorsal Organ, and putative gustatory neurons (marked with arrowheads) with dendrites innervating the Terminal Organ in larvae expressing UAS-mcd8:GFP under the control of the wild-type Or42a-Gal4 or mutant (42a4)-Gal4 [6] (B) Mean number of neurons innervating the Dorsal Organ (DO) and Terminal Organ (TO) in the indicated genotypes. N = 7 (Or42a-Gal4) and N = 13 ((42a4)-Gal4), error bars = s.e.m., T-test, **P<0.0001. (C) Representative confocal Z-projections from larval brains of indicated genotypes. (D) Zoomed in view of a larval antennal lobe from (42a4)-Gal4; UAS-mcd8:GFP counterstained with nc82 (red). (E) Mean number of glomeruli labeled by UAS-mcd8:GFP driven by the indicated promoters. N = 6 for each sample, error bars = s.e.m., T-test, **P<0.01.