Sequence encoding a GAL4 driver has been inserted immediately after the translational start codon of dsx in exon 2, which is common to male and female dsx mRNAs. This GAL4 coding sequence is terminated by a single stop codon. The two codons 3' of the GAL4 stop codon encode different amino acids than those normally found in dsx proteins, but otherwise the dsx sequences both 5' and 3' of the GAL4 insertion site are unaltered in the targeted chromosome. This allele is anticipated, barring internal re-initiation of translation, to be a null dsx allele.
Expression driven by Scer\GAL4dsx-GAL4 was restricted via a transgenic cell class-lineage intersection (CLIn) system to a subset of three clusters of sexually dimorphic neurons - PMP-e, pIP-e and a cluster in the superior medial protocerebrum - of specific Type II neuroblast lineages using Klac\KDRstg14. All but one (59-70) male and all 5 female adult fruitless pMP-e neurons are part of the DM4 lineage, the remaining male pMP-e neuron is part of the DM6 lineage, 27-34 male and 10-16 female pIP-e neurons are part of the DL2 lineage, and 3-5 male and 4 female neurons in the superior medial protocerebrum cluster are part of the DM2 lineage. In total, ~66% (~202/306) male and ~79% (~44/56) female Scer\GAL4dsx-GAL4 neurons intersect with Klac\KDRstg14.
A dsx GAL4 reporter is used to characterize the expression pattern of dsx at all stages of development, but particularly in larvae and adults. An extremely detailed description of the dsx expression pattern is presented with particular attention to whether the pattern is sexually dimorphic in the various tissues. Included is a detailed description of the expression pattern in the adult CNS and in adult peripheral sensory structures.