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， 联系和基因表达。重要的是，稀有细胞类型中的扰动，构成了一小部分 对整个大脑的影响，会导致毁灭性的疾病困扰整个有机体。对于许多疾病来说， 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正在进行的 试图将基因多态与中枢神经系统疾病联系起来的全基因组研究激增。 同样，其他技术也极大地降低了对候选基因重新测序以识别的成本 可能的突变。尽管如此，对不同基因的多态如何导致共同的 疾病通常是不被理解的。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全套基因 在哺乳动物的大脑中。在这里，我们应用此方法来帮助弥合 疾病中的一个基因和一个症状有两种常见的方法。首先，当一种细胞类型被怀疑 在一种疾病中选择性地易受伤害，我们可以识别在疾病中选择性使用的一套基因 这种特定的细胞类型是潜在的疾病候选。第二，当有许多候选基因时 我们可以分析我们的细胞类型特定的翻译图谱来确定这些不同的基因 牵涉到共同的细胞类型或电路。 对于第一种方法，我们分离了5-羟色胺能神经元的完整翻译图谱。AS 长期以来，5-羟色胺能系统的失调一直被怀疑与自闭症有关，我们进行了测试 多重患者群体中5-羟色胺能基因与自闭症之间的关联。我们发现 与两个基因的常见变异相关联，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。我们现在正在老鼠身上重述这种突变，并测试 让人联想到自闭症的行为，以及应用高通量测序来理解 该突变对体外和体内RNA的剪接和翻译的影响。

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.