A subset of antennal Or genes require acj6 for expression. A, In situ hybridizations of Or genes to wild-type and acj66 antennae. Cells are labeled in red. B, Effects of acj66 on receptor expression shown by in situ hybridization (Or42b, Or92a, Or59b, Or85a, Or22a, Or85b) or inferred by response properties of antennal neurons (ab1C, ab1D). The number of Acj6 sites within 1 kb upstream of these genes is indicated.