Functional analysis of fruitless gene expression by transgenic manipulations of Drosophila courtship

Abstract

A gal4-containing enhancer-trap called C309 was previously shown to cause subnormal courtship of Drosophila males toward females and courtship among males when driving a conditional disrupter of synaptic transmission (shi TS ). We extended these manipulations to analyze all features of male-specific behavior, including courtship song, which was almost eliminated by driving shi TS at high temperature. In the context of singing defects and homosexual courtship affected by mutations in the fru gene, a tra-regulated component of the sex-determination hierarchy, we found a C309͞tra F combination also to induce high levels of courtship between pairs of males and ''chaining'' behavior in groups; however, these doubly transgenic males sang normally. Because production of male-specific FRU M protein is regulated by TRA, we hypothesized that a fru-derived transgene encoding the male (M) form of an Inhibitory RNA (fru MIR ) would mimic the effects of tra F ; but C309͞fru MIR males exhibited no courtship chaining, although they courted other males in single-pair tests. Doublelabeling of neurons in which GFP was driven by C309 revealed that 10 of the 20 CNS clusters containing FRU M in wild-type males included coexpressing neurons. Histological analysis of the developing CNS could not rationalize the absence of tra F or fru MIR effects on courtship song, because we found C309 to be coexpressed with FRU M within the same 10 neuronal clusters in pupae. Thus, we hypothesize that elimination of singing behavior by the C309͞shi TS combination involves neurons acting downstream of FRU M cells reproductive behavior ͉ C309 enhancer trap ͉ shi TS transgene ͉ tra F transgene ͉ inhibitory fru RNA transgene

Obesity-Blocking Neurons in Drosophila

“…fruitless (fru) mutations produce males with defective courtship and female-like aggressive displays, and the same behavioral defects are observed in males that express only the female-specific FRUITLESS protein isoform, or have silenced Fru-Gal4 neurons (Manoli et al, 2005; Demir et al, 2005; Stockinger et al, 2005; Villella et al, 2005). These observations would be consistent with the hypothesis that Fru-Gal4-silenced males are obese because they accumulate fat stores like females.…”

ADrosophilaDEG/ENaC Subunit Functions Specifically in Gustatory Neurons Required for Male Courtship Behavior

“…Except where indicated, observation was performed under infrared light in Plexiglass chambers (7mm diameter × 7mm deep). Behaviors were scored blind and analyzed using the LIFESONG X software (version 0.8) (Villella et al, 2005). The Courtship Index is the fraction of time the male spends performing any courtship behavior x100 (Hall, 1978), while we defined a Total Behavioral Index as the fraction of the same ten minute period during which the male courts, walks or preens x100.…”

TwoDrosophilaDEG/ENaC Channel Subunits Have Distinct Functions in Gustatory Neurons That Activate Male Courtship

“…Courtship directed at males was assayed using intact w 1118 males under visible laboratory lights. Behavior was recorded with a digital Mini-DV camera for 10 minutes, scored blind and analyzed using the LIFESONG X software (version 0.8) (Villella et al, 2005). The Courtship Index is the fraction of time the male spends performing any courtship behavior x100 (Hall, 1978), and the Total Behavioral Index is the fraction of the same ten minute period during which the male courts, walks or preens x100 (Starostina et al, 2012).…”