title: A small cohort of FRU(M) and Engrailed-expressing neurons mediate successful copulation in Drosophila melanogaster.
abstract: BACKGROUND
  In Drosophila, male flies require the expression of the male-specific Fruitless protein (FRU(M)) within the developing pupal and adult nervous system in order to produce male courtship and copulation behaviors. Recent evidence has shown that specific subsets of FRU(M) neurons are necessary for particular steps of courtship and copulation. In these neurons, FRU(M) function has been shown to be important for determining sex-specific neuronal characteristics, such as neurotransmitter profile and morphology.
  
  
  RESULTS
  We identified a small cohort of FRU(M) interneurons in the brain and ventral nerve cord by their co-expression with the transcription factor Engrailed (En). We used an En-GAL4 driver to express a fru(M) RNAi construct in order to selectively deplete FRU(M) in these En/FRU(M) co-expressing neurons. In courtship and copulation tests, these males performed male courtship at wild-type levels but were frequently sterile. Sterility was a behavioral phenotype as these En-fru(M)RNAi males were less able to convert a copulation attempt into a stable copulation, or did not maintain copulation for long enough to transfer sperm and/or seminal fluid.
  
  
  CONCLUSIONS
  We have identified a population of interneurons necessary for successful copulation in Drosophila. These data confirm a model in which subsets of FRU(M) neurons participate in independent neuronal circuits necessary for individual steps of male behavior. In addition, we have determined that these neurons in wild-type males have homologues in females and fru mutants, with similar placement, projection patterns, and neurochemical profiles.
authors.affiliation: Department of Zoology, Molecular and Cellular Biology Program, Oregon State University, Corvallis, OR 97331-2914, USA. lathamk@wou.edu
authors.forename: Kristin L
authors.initials: KL
authors.lastname: Latham
authors.forename: Ying-Show
authors.initials: YS
authors.lastname: Liu
authors.forename: Barbara J
authors.initials: BJ
authors.lastname: Taylor
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D001921:Brain / Q000166:cytology*; D003307:Copulation / Q000502:physiology*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster; D005260:Female; D005298:Fertility / Q000235:genetics / Q000502:physiology; D017952:Ganglia, Invertebrate / Q000166:cytology; D018507:Gene Expression Regulation, Developmental / Q000235:genetics / Q000502:physiology*; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D007395:Interneurons / Q000378:metabolism*; D008297:Male; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D011679:Pupa; D034622:RNA Interference / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D029721:Drosophila Proteins; C063459:En protein, Drosophila; D018398:Homeodomain Proteins; D009419:Nerve Tissue Proteins; D014157:Transcription Factors; C103226:fru protein, Drosophila