Kimura Ken-Ichi, Hachiya Tomoaki, Koganezawa Masayuki, Tazawa Tatsunori, Yamamoto Daisuke
Laboratory of Biology, Iwamizawa Campus, Hokkaido University of Education, Iwamizawa 068-8642, Japan.
Neuron. 2008 Sep 11;59(5):759-69. doi: 10.1016/j.neuron.2008.06.007.
Biologists postulate that sexual dimorphism in the brain underlies gender differences in behavior, yet direct evidence for this has been sparse. We identified a male-specific, fruitless (fru)/doublesex (dsx)-coexpressing neuronal cluster, P1, in Drosophila. The artificial induction of a P1 clone in females effectively provokes male-typical behavior in such females even when the other parts of the brain are not masculinized. P1, located in the dorsal posterior brain near the mushroom body, is composed of 20 interneurons, each of which has a primary transversal neurite with extensive ramifications in the bilateral protocerebrum. P1 is fated to die in females through the action of a feminizing protein, DsxF. A masculinizing protein Fru is required in the male brain for correct positioning of the terminals of P1 neurites. Thus, the coordinated actions of two sex determination genes, dsx and fru, confer the unique ability to initiate male-typical sexual behavior on P1 neurons.
生物学家推测，大脑中的性别二态性是行为上性别差异的基础，但对此的直接证据一直很少。我们在果蝇中鉴定出了一个雄性特异性的、同时表达无果（fru）/双性（dsx）的神经元簇，即P1。即使雌性果蝇大脑的其他部分没有雄性化，在其体内人工诱导产生P1克隆也能有效地激发这类雌性果蝇出现雄性典型行为。P1位于大脑后部靠近蘑菇体的背侧，由20个中间神经元组成，每个中间神经元都有一条初级横向神经突，在双侧原脑中有广泛的分支。通过雌性化蛋白DsxF的作用，P1注定会在雌性果蝇中死亡。雄性大脑中需要雄性化蛋白Fru来使P1神经突的末端正确定位。因此，性别决定基因dsx和fru的协同作用赋予了P1神经元启动雄性典型性行为的独特能力。
