Female-biased sexual dimorphism of neurons in Drosophila

果蝇神经元的雌性偏向性二态性

• 批准号: RGPIN-2014-05095
• 负责人: Allan, Douglas
• 金额: $ 4.44万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=629040
• 关键词: Female; biased; sexual; dimorphism; neurons

Our program of research will examine the genetic and cellular determinants of female-specific neuronal circuits in Drosophila melanogaster. Behavioral differences between males and females arise from ~1500 dimorphic neurons. The field has focused on male behavior, thus our understanding has a strong male bias, leaving female behavior poorly understood. Study of males has identified a sex determination cascade that directs Drosophila dimorphism. This cascade centers on sex-specific RNA splicing of the transcription factors doublesex (dsx) and fruitless (fru). In males, dsx and fru-P1 transcripts are spliced into coding dsxM and fruM isoforms. Females express the RNA splicing factor transformer (tra) that directs splicing of the distinct dsxF and the non-coding fruF isoforms. Prevailing models state that the sexual identity of sex-specific neurons is determined by a double switch system mediated by differences in fruitless and doublesex isoform function.PRELIMINARY DATA. We identified the first CNS neurons that are female-specific, the Ilp7-motoneurons (see Research Contribution 1). We found that the genetic regulation of their generation defies conventional models. In particular, Ilp7-neurons are generated independently of the function of fruitless and doublesex.HYPOTHESIS: We hypothesize that the generation of female-specific neurons and circuits requires novel genetic mechanisms that are distinct from those defined in males.AIM 1) Determine the cellular mechanisms underlying the generation of female-specific neuronal populations. Aim 1A) Determine the fate of female-specific neurons in males. We will use a battery of genetic approaches to test whether the male counterparts die or transfate. Aim 1B) We will identify other female-specific neurons to expand our analysis and uncover common principals. Aim 1Bi takes a targeted approach to identify female reproductive tract neurons and their male counterparts. Aim 1Bii takes advantage of the fact that many neurons become male specific due to their death in female. We will identify dying dimorphic neurons in males using a 'positive identification' protocol. AIM 2) Determine the genetic mechanisms directing female-specific neuron dimorphism. We focus on the roles of tra, fru, dsx, as well as the poorly studied, but described, regulators of female dimorphism, dissatisfaction, intersex and hermaphrodite. In Aim 2A, we examine their roles in known female-specific neurons and in neuronal subset that we expect to be female-specific. In Aim 2B, we take a broader view to examine the roles of these regulators in generating the unique female-type morphologies and gene expression profiles of all dimorphic neuronal populations.AIM 3) Determine the genetic regulation of the formation of female-specific circuits. Aim 3A examines the connectivity between neurons (identified in Aim 1B) that coordinately regulate the female reproductive tract. Aim 3B examines the female-specific connectivity of circuits that are known to have different function in male and females. These studies will be performed by a combination of intersectional reporter genetics and split GFP methods that positively identify synaptic connectivity between specific neurons.IMPACT AND TRAINING. These studies will provide an in depth understanding of how female-specific neuronal circuits are constructed and function, providing an important counterpoint to the decades of analysis of male circuits that generate male-specific behaviors. Students working on this project will obtain valuable training in advanced Drosophila molecular genetics, 3D neuronal imaging and behavioral analysis.

我们的研究计划将探讨遗传和细胞的决定因素，女性特有的神经元回路在果蝇。雄性和雌性之间的行为差异来自约1500个双态神经元。该领域的重点是男性行为，因此我们的理解有很强的男性偏见，使女性行为知之甚少。对雄性果蝇的研究已经确定了一种性别决定级联反应，这种级联反应决定了果蝇的二型性。这种级联反应集中在转录因子doublemex（dsx）和fruitless（fru）的性别特异性RNA剪接上。在雄性中，dsx和fru-P1转录物被剪接成编码dsxM和fruM同种型。雌性表达RNA剪接因子Transformer（tra），其指导不同dsxF和非编码fruF同种型的剪接。流行的模型指出，性别特异性神经元的性别身份是由一个双开关系统介导的无结果和doublemex同种型功能的差异。我们确定了第一个女性特有的CNS神经元，即Ilp 7运动神经元（见研究贡献1）。我们发现，他们这一代的遗传调控违背了传统模型。特别是，Ilp 7-神经元产生独立的功能，无果而终和doubletex.Hypothesis：我们假设，产生女性特定的神经元和电路需要新的遗传机制，是不同于那些定义在males.AIM 1）确定的细胞机制的基础上产生的女性特定的神经元群体。目的1A）确定雌性特异性神经元在雄性中的命运。我们将使用一系列遗传学方法来测试男性是否会死亡或转移。目的1B）我们将识别其他女性特异性神经元，以扩展我们的分析并揭示共同的原则。目的1Bi采用有针对性的方法识别女性生殖道神经元和它们的男性对应神经元。目的1Bii利用了这样一个事实，即许多神经元由于在女性中死亡而成为男性特异性的。我们将使用“阳性识别”协议来识别男性中垂死的二型神经元。目的2）探讨雌性特异性神经元二型性的遗传机制。我们关注的角色tra，fru，dsx，以及研究不足，但描述，调节女性二型性，不满，双性和雌雄同体。在目标2A中，我们研究了它们在已知的女性特异性神经元和我们期望是女性特异性的神经元子集中的作用。在目标2B中，我们从更广泛的角度来研究这些调控因子在产生所有二态性神经元群体的独特雌性型形态和基因表达谱中的作用。目的3A检查协调调节雌性生殖道的神经元（在目的1B中鉴定）之间的连接。目的3B检查已知在男性和女性中具有不同功能的电路的女性特异性连接。这些研究将通过交叉报告基因学和分裂GFP方法的组合进行，这些方法可以明确识别特定神经元之间的突触连接。这些研究将深入了解女性特有的神经元回路是如何构建和发挥作用的，为数十年来对产生男性特有行为的男性回路的分析提供了重要的对比。从事该项目的学生将获得先进的果蝇分子遗传学，3D神经元成像和行为分析方面的宝贵培训。