Sexual behavior mutants revisited: molecular and cellular basis of Drosophila mating

Abstract

The study of Drosophila melanogaster by a combination of forward genetics with specific mutants, and reverse genetics, in which a given gene is expressed in an appropriate brain area to test its effect on behavior, provides a unique opportunity to explore the causal relationship between a particular gene, its function in the cell and the behavioral outcome at the organismic level. Enhanced male-to-male courtship has been shown to occur as a result of mutations in several different genes. For example, the Voila mutant exhibits intense GAL4 reporter expression in the tarsal gustatory sensilla, suggesting the importance of tapping by a male on the female abdomen with his forelegs. Feminization of parts of the antennal lobe and mushroom body by targeted expression of a female-determining gene transformer+ (tra+) drives the male to court other males. Mutations in the tra target gene fruitless (fru), which is expressed in the antennal lobe as well as the suboesophageal ganglion (the gustatory inputs are processed here), also induce homosexual courtship in males. These results suggest that sensory inputs mediated and/or processed by the tarsal receptors, suboesophageal ganglion, antennal lobe and mushroom body contribute to the regulation of male-female courtship. Mosaic analysis localized the neural center for male courtship behavior to the posterior dorsal brain, in which the sensory information processed by the aforementioned neural structures may be integrated. Another mosaic study mapped the neural center for female sexual behavior, as measured by her receptiveness to copulation, to the anterior dorsal brain. The issue as to how the mutations that reduce female sexual receptiveness, e.g. dissatisfaction (dsf), spinster (spin) and chaste (cht), affect the structure and/or function of this neural center deserves to be addressed urgently.

Morphogens and synaptogenesis in Drosophila

“…Two of these genes are spinster (spin) (Yamamoto and Nakano, 1999;Nakano et al, 2001) and highwire (hiw) (Wan et al, 2000), which encode proteins that down-regulate the Wit pathway in motoneurons (Sweeney and Davis, 2002;McCabe et al, 2004). Hiw is a putative E3 ubiquitin ligase that appears to target Medea for proteosomal degradation, preventing over-activation of the pathway.…”

Increased Dopamine Level Enhances Male–Male Courtship inDrosophila

“…Drosophila male courtship and mate discrimination mostly depends on the perception of visual, pheromonal, and acoustic signals exchanged by flies (Yamamoto and Nakano, 1999;Greenspan and Ferveur, 2000). To assess their involvement in the increased intensity of male-male courtship behavior shown by TH-GAL4/UAS-TH males, we experimentally eliminated the effect of each type of signal and measured the behavioral effect (CI and ChI) following each type of sensory deprivation (Fig.…”

New reproductive anomalies in fruitless‐mutant Drosophila males: Extreme lengthening of mating durations and infertility correlated with defective serotonergic innervation of reproductive organs

“…In Drosophila melanogaster, genes functioning in the sex-determination hierarchy (SDH) control sexual differentiation, including establishment of the potential for courtship behavior. The fruitless (fru) gene acts within this hierarchy (reviewed by Goodwin, 1999) and has long been known to influence premating stages of male courtship (reviewed by Hall, 1994;Yamamoto and Nakano, 1999;Greenspan and Ferveur, 2000).…”