Fig. 7.

Loss of pnt leads to duplication of Or67d OSNs. a Phenotypes of control and pnt RNAi when driven with the constitutive and late drivers in antennae expressing the Or67d-CD8a:GFP reporter (green). Two independent pnt RNAi lines—KK100473 (#1) and JF02227 (#2), which target different genomic sequences within an exon common to all four pnt isoforms—result in doublets of GFP-positive neurons, compared to the predominant singlets of these neurons in controls. Late induction of RNAi produces few doublets. The lower images show the magnified views of the region within the dashed box in the upper images. Quantifications of the fraction of singlets/doublets are shown in the stacked histograms at the bottom. White scale bar = 20 µm in this and other panels. b pnt RNAi when driven with at1 driver in antennae expressing the Or67d-CD8a:GFP reporter produces OSN doublets. Due to the relatively weak late expression of the at1 driver, we increased GAL4 dosage either through inclusion of two copies of the driver (left) or an auto-amplifying UAS-GAL4 transgene (right). While the driver is restricted to about half of the at1 lineages (Fig. 4b), Or67d-CD8a:GFP is expressed in both at1 and, ectopically, ab5 ¹³. Based upon the 2:1 ratio of the numbers of at1 and ab5 sensilla³⁷, the maximum percentage of doublets expected in these RNAi experiments is ∼33%, shown by the length of the blue arrows with dashed lines (i.e. half of the at1/Or67d neurons, which represent 66% of all the neurons labeled by this reporter); this is the approximate percentage observed in both genetic manipulations. c Control at1 sensilla have a single Or67d mRNA-expressing OSN (magenta). In pnt RNAi antennae, Or67d mRNA is detected in doublets of OSNs. Yellow scale bar = 2 µm in this and other panels. d Representative MARCM clones of control and pnt null mutant neurons, marked with CD8a:GFP (green). Or67d mRNA-expressing OSNs (magenta) in control clones are singlets, while those in pnt mutant clones are doublets