Serotonin, Autism, and investigating cell types for CNS disorders.

神经系统由数百种不同的细胞类型组成，每种细胞都有独特的形态， 连接和基因表达。重要的是，在罕见的细胞类型，构成一小部分扰动 整个大脑，可能会导致破坏性的疾病折磨整个有机体。对于许多疾病， 这种疾病背后的电路和细胞尚不清楚。最近的技术进步推动了一个持续的 试图将遗传多态性与CNS疾病联系起来的全基因组研究的激增。 同样，其他技术也大大降低了重新测序候选基因的成本， 假定的突变尽管如此，对各种基因多态性的理解可以导致一个共同的 疾病一般不了解。我们最近开发了一种方法。翻译核糖体 亲和纯化（TRAP），分离任何特定细胞类型所使用的完整基因组 在哺乳动物的大脑中。在这里，我们应用这种方法来帮助弥合 一个基因和一个症状在一种疾病中有两种一般的方法。首先，当一种细胞类型被怀疑 在疾病中选择性地脆弱，我们可以识别出在疾病中选择性使用的基因组， 这种特定的细胞类型作为潜在的疾病候选者。第二，当有许多候选基因时， 已知，我们可以分析我们的细胞类型特异性翻译谱，以确定这些不同的基因， 涉及共同细胞类型或电路。 对于第一种方法，我们已经分离出完整的翻译谱的多巴胺能神经元。作为 长期以来，人们一直怀疑多巴胺能系统的失调与自闭症有关，我们已经测试了 在一个大的多元患者群体中，研究了多巴胺能基因与自闭症之间的关联。我们发现 与两个基因中的常见变异相关，并在其中一个基因中发现了一种有害的罕见变异。 基因，RNA结合蛋白BRUN0L6。我们现在正在小鼠身上重现这种突变， 行为让人想起自闭症，以及应用高通量测序来了解 这种突变在体外和体内对RNA的剪接和翻译的结果。

The nervous system is connposed of hundreds of distinct cell types, each with unique morphology, connections, and gene expression. Importantly, perturbations in rare cell types, composing a small fraction of the entire brain, can result in devastating disorders afflicting the entire organism. For many disorders, the circuits and cells underlying the disease are unknown. Recent technical advances have driven an ongoing explosion of genome wide studies attempting to associate genetic polymorphisms with disorders of the CNS. Likewise, other technologies have dramatically reduced the cost of resequencing candidate genes to identify putative mutations. Still, the understanding of how polymorphisms in various genes can lead to a common disease is generally not understood. We have recently developed a methodology. Translating Ribosome Affinity Purification (TRAP), to isolate the complete suite of genes being employed by any particular cell type in the mammalian brain. Here, we apply this methodology to help bridge the gap between a polymorphism in a gene and a symptom in a disorder with two general approaches. First, when a cell type is suspected of being selectively vulnerable in a disorder, we can identify the suite of genes that are employed selectively in that particular cell type as potential disease candidates. Second, when there are many candidate genes known, we can analyze our cell-type specific translational profiles to determine if these various genes implicate a common cell type or circuit. For the first approach, we have isolated the complete translational profile of serotonergic neurons. As dysregulation of the serotonergic system has long been suspected to be involved in autism, we have tested the association between the serotonergic genes and autism in a large multiplex patient population. We found association with common variants in two genes, and identified a deleterious rare variant in one of these genes, the RNA binding protein BRUN0L6. We are now recapitulating this mutation in mice and testing for behaviors reminiscent of autism, as well as applying high-throughput sequencing to understand the consequence of this mutation on splicing and translation of RNA in vitro and in vivo.