Molecular Mechanisms of Thalamocortical Development

描述（由申请人提供）：大脑皮层通过丘脑接收和发送信息来调节感知和运动控制。一些神经系统疾病，如精神发育迟滞、癫痫和精神分裂症，似乎与大脑皮层的神经发育缺陷有关。本研究将采用正向遗传学方法研究丘脑皮质轴突（TCA）发育的分子机制。具体目的一：利用特异性报告基因筛选丘脑皮质发育缺陷的小鼠突变体。TCA-TLZ（丘脑皮质轴突-tau-lacZ）报告线允许在整个大脑中可视化TCA而无需切片，因此提供了一种独特的工具，用于快速筛选丘脑皮质发育缺陷。将对报告细胞系进行诱变，并分析胚胎第18天第三代后代的脑缺陷。筛查胚胎将使致命突变得以恢复。这位记者将揭示丘脑轴突导向和皮质分层的缺陷。具体目的II：表征筛选中鉴定的突变体的表型。将使用tau-lacZ标记以及标准神经解剖学和组织学方法在几个发育阶段检查突变脑，以确定观察到的表型的程度和原因。 具体目标III：定位克隆在筛选中鉴定的代表最感兴趣的表型和新基因座的一个或两个基因。在高分辨率定位后，将通过突变体的外显子的表达和测序来检查候选基因以发现突变。作为一名神经科学家，候选人有着出色的记录，但希望在开始一个独立的实验室研究大脑皮层发育的分子机制之前，接受小鼠遗传学方面的额外培训。在博士阶段，C. elegans遗传学被用于研究神经元如何将蛋白质靶向特定的膜结构域。过渡到啮齿类动物系统研究皮质发育，使用组织学和神经解剖学技术。为了将小鼠遗传学加入到技能组合中，候选人已经安排与哈佛医学院的克里斯托弗沃尔什博士和大卫贝尔博士共同工作。将小鼠遗传学方面的专业知识与先前在小鼠神经解剖学和线虫遗传学方面的培训相结合，将大大增加候选人对该领域产生重大影响的潜力。

DESCRIPTION (provided by applicant): The cerebral cortex mediates perceptions and motor control by receiving and sending information through the thalamus. Some neurological disorders such as mental retardation, epilepsy, and schizophrenia appear to involve developmental defects in the wiring of the cerebral cortex. Molecular mechanisms of thalamocortical axon (TCA) development will be studied by taking a forward genetics approach. Specific Aim I: To peform a screen for mouse mutants with defects in thalamocortical development, using a specific reporter. The TCA-TLZ (thalamocortical axon-tau-lacZ) reporter line allows visualization of TCAs in whole brains without slicing, and therefore provides a unique tool with which to rapidly screen for defects in thalamocortical development. The reporter line will be mutagenized and the brains of third-generation progeny at embryonic day 18 will be analyzed for defects. Screening embryos will enable recovery of lethal mutations. This reporter will reveal defects in thalamic axon guidance and cortical lamination. Specific Aim Il: To characterize the phenotypes of mutants identified in the screen. Mutant brains will be examined at several developmental stages using the tau-lacZ marker as well as standard neuroanatomical and histological methods to determine the extent and cause of the phenotypes observed. Specific Aim Ill: To positionally clone one or two genes identified in the screen that represent the most interesting phenotypes and novel loci. After high resolution mapping, candidate genes will be examined by expression and sequencing of exons from the mutants to find the mutations. The Candidate has an excellent record so far as a neuroscientist, but wishes to receive additional training in mouse genetics before starting an independent laboratory to study the molecular mechanisms underlying cortical development. In the Ph.D., C. elegans genetics was used to study how neurons target proteins to specific membrane domains. A transition was made to the rodent system to study cortical development using histological and neuroanatomical techniques. To add mouse genetics to the skill set, the candidate has arranged to work jointly with Dr. Christopher Walsh and Dr. David Beier, both at Harvard Medical School. Combining the expertise in mouse genetics with the previous training in mouse neuroanatomy and nematode genetics will significantly add to the Candidate's potential to make a strong impact on the field.