Chan Yick-Bun, Kravitz Edward A
Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA.
Proc Natl Acad Sci U S A. 2007 Dec 4;104(49):19577-82. doi: 10.1073/pnas.0709803104. Epub 2007 Nov 27.
A great challenge facing neuroscience is to understand how genes, molecules, cells, circuits, and systems interact to generate social behavior. Fruit flies (Drosophila melanogaster) offer a powerful model system to address questions of this magnitude. These animals display genetically specified, sexually dimorphic patterns of fighting behavior via sex-specific splicing of the fruitless gene. Here, we show that sexually dimorphic behavioral patterns displayed during aggression are controlled by specific subgroups of neurons expressing male forms of fruitless proteins (Fru(M)). Using the GAL4/UAS system to manipulate transformer expression, we feminized or masculinized different populations of neurons in fly nervous systems. With a panneuronal elav-GAL4 driver, male patterns of fighting behavior were transferred into females and female patterns into males. We screened 60 Gal4 lines that express the yeast transcription factor in different patterns in fly central nervous systems and found five that showed abnormal same-sex courtship behavior. The sexually dimorphic fighting patterns, however, were completely switched only in one and partially switched in a second of these lines. In the other three lines, female patterns of aggression were seen despite a switch in courtship preference. A tight correspondence was seen between Fru(M) expression and how flies fight in several subgroups of neurons usually expressing these proteins: Expression is absent when flies fight like females and present when flies fight like males, thereby beginning a separation between courtship and aggression among these neurons.
神经科学面临的一个巨大挑战是理解基因、分子、细胞、神经回路和系统如何相互作用以产生社会行为。果蝇（黑腹果蝇）提供了一个强大的模型系统来解决这类重大问题。这些动物通过无果基因的性别特异性剪接表现出基因指定的、两性异形的战斗行为模式。在这里，我们表明，攻击过程中表现出的两性异形行为模式由表达雄性形式无果蛋白（Fru(M)）的特定神经元亚群控制。利用GAL4/UAS系统操纵transformer的表达，我们使果蝇神经系统中不同的神经元群体雌性化或雄性化。使用泛神经元elav-GAL4驱动子，雄性战斗行为模式被转移到雌性中，而雌性模式则被转移到雄性中。我们筛选了60个在果蝇中枢神经系统中以不同模式表达酵母转录因子的Gal4品系，发现其中5个表现出异常的同性求偶行为。然而，两性异形的战斗模式仅在其中一个品系中完全转变，在另一个品系中部分转变。在其他三个品系中，尽管求偶偏好发生了转变，但仍观察到雌性的攻击模式。在通常表达这些蛋白的几个神经元亚群中，可以看到Fru(M)的表达与果蝇的战斗方式之间存在紧密的对应关系：当果蝇像雌性一样战斗时，表达缺失；当果蝇像雄性一样战斗时，表达存在，从而在这些神经元之间开始了求偶和攻击行为的分化。
