Elucidation of the developmental role of Jakmip1, and autism-susceptibility gene

描述（由申请人提供）：研究自闭症遗传基础的一个主要挑战是，许多基因与这种疾病有关，但每个基因只占病例的一小部分。为了开发能够帮助更多自闭症患者的治疗方法，我们必须识别和理解那些普遍失调的基因。为此，我们的研究小组研究了两组已知遗传原因的自闭症患者与健康对照组之间共有的全基因组表达变化。Janus激酶和微管相互作用蛋白1 （JAKMIP1）是该筛选中最受欢迎的基因之一，并在另一组原因不明的自闭症患者中得到了验证。JAKMIP1是一个重要的自闭症候选基因，原因有三。首先，它主要在神经元中表达。其次，JAKMIP1调节GABA受体的表达和可能的转运，已知GABA能系统在自闭症中异常。最后，JAKMIP1是单基因导致自闭症的下游基因。JAKMIP1的一个重要方面是它包含四种脑特异性亚型，A， B， C和D，它们在小鼠和人类之间是保守的，并且具有不同的功能域。我的项目旨在了解不规则的Jakmip1异构体水平如何破坏保守的发育过程，从而导致自闭症病理。Aim 1A将确定在发育和整个成年期间，哪些亚型在蛋白质和转录水平上表达。我会在整个发育过程中从大脑皮层和小脑这两个受自闭症影响的大脑区域收集蛋白质和mRNA，并使用western blotting和定量实时PCR来确定表达变化。Aim 1B将通过免疫组织化学和亚型特异性抗体阐明Jakmip1亚型在发育和成人大脑中的分布，以及这些亚型所处的神经元亚型。Aim 2A将使用shRNA和微阵列技术确定沉默Jakmip1亚型对分化小鼠神经祖细胞的转录组影响。最后，Aim 2B将评估分化小鼠神经祖细胞刺激前后Jakmip1亚型表达减少导致的神经突形态变化和树突定位mRNA群体构成的扰动。我将采用最近的技术（Poon et al. 2006）从细胞体中分离树突、轴突和胶质突来进行Aim 2B。这项研究将揭示异常JAKMIP1水平导致自闭症的机制，并可能进一步暗示JAKMIP1是自闭症易感基因。这些发现将有助于自闭症儿童的症状前诊断和早期行为干预，以及药物的设计。

DESCRIPTION (provided by applicant): A major challenge in studying the genetic basis of autism is that many genes are associated with the disorder, but each only accounts for a fraction of the cases. To develop treatments that will help a wide range of autistic subjects, we must identify and understand those genes that are commonly dysregulated. To this end, our group looked at shared genome-wide expression changes across two groups of autistic patients with known genetic causes vs. healthy controls. Janus kinase and microtubule-interacting protein 1, JAKMIP1, was one of the top hits from this screen and was validated in a separate group of autistic patients with unknown causes. JAKMIP1 is an important autism-candidate gene for three reasons. First, it is expressed predominantly in neurons. Secondly, JAKMIP1 regulates the expression and possible transport of GABA receptors and GABAergic systems are known to be abnormal in the autisms. Lastly, JAKMIP1 is downstream of genes that monogenetically cause autism. An important aspect of JAKMIP1 is that is contains four brain-specific isoforms, A, B, C and D, that are conserved between mouse and human and have distinct functional domains. My project aims to understand how irregular Jakmip1 isoform levels could disrupt conserved developmental processes, contributing to autism pathology. Aim 1A will determine which isoforms are expressed at the protein and transcript level during development and throughout adulthood. I will collect protein and mRNA from the cortex and cerebellum, two brain regions affected in autism, throughout development and will determine expression changes using western blotting and quantitative real time PCR. Aim 1B will elucidate the distribution of Jakmip1's isoforms in the developing and adult brain and in which neuronal subtypes these isoforms are located by using immunohistochemistry and isoform-specific antibodies. Aim 2A will ascertain the transcriptome-wide impact of silencing Jakmip1's isoforms in differentiated mouse neural progenitors using shRNA and microarray technology. Lastly, Aim 2B will assess neurite morphological changes and perturbations in the population make-up of dendritically-localized mRNA resulting from decreasing Jakmip1 isoform expression in differentiated mouse neural progenitors pre and post stimulation. I will carry out Aim 2B by employing a recent technique (Poon et al. 2006) to isolate and separate dendritic, axonal, and glial processes from the cell body. This study will shed light on the mechanism by which aberrant JAKMIP1 levels could result in autism and may further implicate JAKMIP1 as an autism-susceptibility gene. These discoveries will aid in pre-symptomatic diagnosis and early behavioral intervention for autistic children as well as the design of pharmaceuticals.