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: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=611436
• 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.

我们的研究计划将检查果蝇果蝇中女性特异性神经元回路的遗传和细胞决定因素。男性和女性之间的行为差​​异来自约1500个二态神经元。该领域的重点是男性行为，因此我们的理解具有强烈的男性偏见，使女性的行为理解不佳。对男性的研究确定了指导果蝇二态性的性别确定级联。这一级联集中于转录因子的性别特异性RNA剪接Doublesex（DSX）和毫无结果（FRU）。在男性中，DSX和FRU-P1转录本被剪接为编码DSXM和FRUM同工型。雌性表达RNA剪接因子变压器（TRA），该RNA剪接因子指导不同的DSXF和非编码FRUF同工型的剪接。流行模型指出，性别特异性神经元的性认同是由双开关系统确定的，这是由徒劳和doublesex同工型功能的差异介导的。 初步数据。我们确定了女性特异性的第一个CNS神经元，即ILP7------------------参见研究贡献1）。我们发现其一代的遗传调节违反了常规模型。特别是，ILP7-神经元独立于无效和doublesex的功能。 假设：我们假设女性特异性神经元和回路的产生需要与男性定义的新型遗传机制不同。 目标1）确定女性特异性神经元种群产生的基础的细胞机制。目标1A）确定雄性女性特异性神经元的命运。我们将使用一系列遗传方法来测试男性对同行是死亡还是转运。目的1B）我们将确定其他特定女性的神经元，以扩大我们的分析并发现共同的原理。 AIM 1BI采用靶向方法来识别女性生殖道神经元及其男性同伴。 AIM 1BII利用了许多神经元因女性死亡而变得明确的事实。我们将使用“阳性识别”方案确定男性中垂死的二态神经元。 目标2）确定指导女性特异性神经元二态性的遗传机制。我们专注于Tra，Fru，DSX的角色，以及所研究的较少但描述的女性二态性，不满，双性恋和雌雄同体的调节剂。在AIM 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AIM 2B中，我们采用更广泛的观点来研究这些调节剂在产生所有二态神经元种群的独特女性型形态和基因表达谱的作用。 目标3）确定女性特异性电路形成的遗传调节。 AIM 3A检查了协调调节女性生殖道的神经元（在AIM 1B中识别）之间的连通性。 AIM 3B检查了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通性。这些研究将通过相互分裂的遗传学和分裂GFP方法的组合进行，从而积极地识别特定神经元之间的突触连通性。 影响和训练。这些研究将深入了解女性特异性神经元回路并发挥作用，从而对几十年来对产生男性特异性行为的男性回路进行了重要的对立。从事该项目的学生将获得高级果蝇分子遗传学，3D神经元成像和行为分析的宝贵培训。