Molecular identification of genes critical for vertebrate startle modulation

对脊椎动物惊吓调节至关重要的基因的分子鉴定

• 批准号: 8678297
• 负责人: Michael Granato
• 金额: $ 24万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-04-14 至 2016-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8678297
• 关键词: Acoustics; Adaptor Protein Complex 2; Animals; Applications Grants; Attention Deficit Disorder; Behavior; Behavioral; Candidate Disease Gene; Characteristics; Cloning; Cognition Disorders; Communities; Complex; Defect; Disease; Drug abuse; Elements; Etiology; Exhibits; Funding; Gene Mutation; Gene Order; Gene Transfer Techniques; Genes; Genetic; Genetic Screening; Genome; Genotype; Grant; Human; Huntington Disease; Injection of therapeutic agent; Larva; Learning; Link; Maps; Measures; Mental Health; Messenger RNA; Molecular; Motor; Mutation; Nervous System Physiology; Nervous system structure; Neurons; Neurosciences; Nonsense Codon; Obsessive-Compulsive Disorder; Patients; Performance; Phenotype; Plasma Proteins; Positioning Attribute; Post-Traumatic Stress Disorders; Pregnancy; Process; RNA Splicing; Reflex action; Role; Schizophrenia; Sensory; Sequence Analysis; Stereotyping; Stimulus; System; Vertebrates; Zebrafish; conditioned fear; gene function; genetic manipulation; genome sequencing; in vivo; innovation; insight; kinematics; mutant; neural circuit; neuromechanism; neuropsychiatry; public health relevance; response; screening

DESCRIPTION (provided by applicant): A remarkable feature of the nervous system is its ability to adjust stereotyped behavioral responses in a context dependent manner. For example, sudden and intense acoustic stimuli evoke the evolutionarily conserved startle response. While the execution of the acoustic startle response is extremely stereotyped, response initiation is modulated in a context-dependent manner. For example, repeated presentation of a startling stimulus suppresses the startle response, representing a simple form of learning known as habituation. Similarly, response threshold and thus startle sensitivity are also modulated in a context- dependent manner, such that for fear-conditioned animals otherwise sub-threshold stimuli are now sufficient to evoke a startle response. In humans, startle modulation -as measured by habituation or startle sensitivity- is impaired in several neuropsychiatric disorders, including schizophrenia, attention deficit disorder, Huntington's disease, obsessive-compulsive disorder (OCD) as well as in patients suffering from post-traumatic stress disorders (PTSD). Despite its importance, the molecular mechanisms underlying acoustic startle modulation are poorly understood. Zebrafish show a remarkable behavioral plasticity, and we have previously shown that larvae exhibit modulation of the acoustic startle response- including sensitivity and habituation- with landmark behavioral and pharmacological characteristics. Moreover, the neural circuit elements executing the zebrafish startle response have been defined, and due to its transparency larvae are amenable to genetic and opto-genetic manipulations. Using an automated system, we conducted the first forward genetic screen in vertebrates to identify genes required for acoustic startle modulation. We identified 24 mutants with defects in startle responsiveness to sub-threshold acoustic stimuli, defects in short-term habituation, or defects in both. None of these 24 mutants exhibit any gross morphological defects or defects in startle performance. By applying whole genome sequencing to two of these mutants, we identified gene mutations in the adaptor-related protein complex 2 sigma 1 subunit (ap2s1), and in the vertebrate specific pregnancy associated plasma protein-a (papp-a), respectively. Importantly, neither of these genes has previously been implicated in regulating habituation or startle sensitivity, suggesting that many of the remaining (un-cloned) 22 mutants may encode genes with critical roles in startle modulation previously not implicated in this process. Here, we propose to apply whole genome sequencing to the remaining 22 mutants to genetically map and identify the underlying causative mutations. Combined our results will increase the scientific impact of these mutants for the entire neuroscience community by creating an unparalleled platform for integrative studies to decipher the molecular and neural mechanisms underlying 'normal' startle modulation, and provide insights into neuropsychiatric disorders associated with impaired startle modulation, such as schizophrenia, OCD and PTSD.

描述(由申请人提供)：神经系统的一个显著特征是它能够以依赖于环境的方式调整刻板印象的行为反应。例如，突然而强烈的声音刺激会唤起进化上保守的惊吓反应。虽然声学惊吓反应的执行是非常刻板的，但反应的启动是以一种依赖于上下文的方式调节的。例如，重复呈现令人震惊的刺激会抑制惊吓反应，这代表了一种被称为习惯化的简单学习形式。类似地，反应阈值和惊吓敏感性也是以上下文相关的方式调节的，因此对于恐惧条件下的动物来说，其他低于阈值的刺激现在足以唤起惊吓反应。在人类中，惊吓调制--通过习惯性或惊吓敏感性来衡量--在几种神经精神障碍中受到损害，包括精神分裂症、注意力缺陷障碍、亨廷顿氏病、强迫症(OCD)以及患有创伤后应激障碍(PTSD)的患者。尽管它很重要，但声学惊吓调制背后的分子机制却知之甚少。斑马鱼表现出显著的行为可塑性，我们之前已经证明，幼虫表现出声学惊吓反应的调制-包括敏感性和习惯化-具有里程碑式的行为和药理学特征。此外，执行斑马鱼惊吓反应的神经回路元件已经被定义，由于其透明度，幼虫可以接受遗传和光遗传操作。使用自动化系统，我们在脊椎动物中进行了第一次正向基因筛查，以识别声学惊吓调制所需的基因。我们确定了24个突变体，它们对亚阈值声音刺激的惊吓反应存在缺陷，短期适应能力存在缺陷，或者两者都存在缺陷。这24个突变体都没有表现出任何明显的形态缺陷或惊吓表现上的缺陷。通过对其中两个突变体进行全基因组测序，我们分别鉴定了适配器相关蛋白复合体2西格玛1亚单位(Ap2s1)和脊椎动物特异性妊娠相关血浆蛋白-a(PAPP-a)的基因突变。重要的是，这两个基因以前都没有涉及到调节习惯性或惊吓敏感性，这表明剩余的(未克隆的)22个突变体中的许多可能编码在惊吓调节中具有关键作用的基因，此前并未涉及这一过程。在这里，我们建议将全基因组测序应用于剩余的22个突变，以遗传图谱和识别潜在的致病突变。综合我们的结果，我们将通过创建一个无与伦比的综合研究平台来提高这些突变体对整个神经科学界的科学影响，以破译“正常”惊吓调制背后的分子和神经机制，并为与惊吓调制受损相关的神经精神疾病提供见解，如精神分裂症、强迫症和创伤后应激障碍。