title: The Sex Determination Gene transformer Regulates Male-Female Differences in Drosophila Body Size.
abstract: Almost all animals show sex differences in body size. For example, in Drosophila, females are larger than males. Although Drosophila is widely used as a model to study growth, the mechanisms underlying this male-female difference in size remain unclear. Here, we describe a novel role for the sex determination gene transformer (tra) in promoting female body growth. Normally, Tra is expressed only in females. We find that loss of Tra in female larvae decreases body size, while ectopic Tra expression in males increases body size. Although we find that Tra exerts autonomous effects on cell size, we also discovered that Tra expression in the fat body augments female body size in a non cell-autonomous manner. These effects of Tra do not require its only known targets doublesex and fruitless. Instead, Tra expression in the female fat body promotes growth by stimulating the secretion of insulin-like peptides from insulin producing cells in the brain. Our data suggest a model of sex-specific growth in which body size is regulated by a previously unrecognized branch of the sex determination pathway, and identify Tra as a novel link between sex and the conserved insulin signaling pathway.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta, Canada.|Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Rideout
authors.affiliation: Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Marcus S
authors.initials: MS
authors.lastname: Narsaiya
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Savraj S
authors.initials: SS
authors.lastname: Grewal
mesh_terms: D000818:Animals; D049628:Body Size / Q000235:genetics*; D001921:Brain / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics; D004330:Drosophila / Q000235:genetics* / Q000254:growth & development; D029721:Drosophila Proteins / Q000235:genetics; D005216:Fat Body / Q000378:metabolism; D005260:Female; D007328:Insulin / Q000378:metabolism; D008297:Male; D009419:Nerve Tissue Proteins / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D012727:Sex Characteristics; D019849:Sex Determination Processes / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics
chemical_list: D004268:DNA-Binding Proteins; C070369:DSX protein, Drosophila; D029721:Drosophila Proteins; D007328:Insulin; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; C097162:Tra protein, Drosophila; D014157:Transcription Factors; C103226:fru protein, Drosophila