Mutational analysis to understand the role of CHML in developmental regression

突变分析以了解 CHML 在发育回归中的作用

基本信息

批准号：
8877784
负责人：
Eugene Yu
金额：
$ 23.69万
依托单位：
ROSWELL PARK CANCER INSTITUTE CORP
依托单位国家：
美国
项目类别：
财政年份：
2015
资助国家：
美国
起止时间：
2015-06-01 至 2017-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8877784
关键词：
Affect Affinity Alleles Alzheimer&apos s Disease Amino Acid Sequence Apoptosis Autophagocytosis Behavioral Biological Process Biomedical Research Brain Candidate Disease Gene Cell physiology Cells Choroid Choroideremia Clinical Clustered Regularly Interspaced Short Palindromic Repeats Code Complementary DNA Complex Cytokinesis Development Disease Employee Strikes Engineering Enrollment Event Evolution Exhibits Eye Family Financial compensation Foundations Future GTP-Binding Proteins Genes Genetic Genome Genomics Genotype Goals Guanosine Triphosphate Phosphohydrolases Heterozygote Histocompatibility Testing Human Inherited Knock-out Lead Link Magnetic Resonance Imaging Mammals Mediating Membrane Membrane Protein Traffic Messenger RNA Missense Mutation Modeling Molecular Motor Mus Mutant Strains Mice Mutation Nerve Degeneration Neuraxis Neurodegenerative Disorders Nonsense Mutation Organ Organism Orthologous Gene Parents Patients Peptide Sequence Determination Phenotype Photoreceptors Play Proteins Rab escort protein Rare Diseases Reporting Reverse Transcription Role Siblings Specificity Structure Structure of retinal pigment epithelium System Testing Therapeutic Intervention Therapeutic Studies Time Tissues United States National Institutes of Health Zebrafish autism spectrum disorder base body system brain tissue cell motility cilium biogenesis cognitive function design intercellular communication loss of function mouse model mutant novel novel therapeutic intervention null mutation paralogous gene prenylation prevent programs public health relevance response success white matter

项目摘要

DESCRIPTION (provided by applicant): Studies on rare diseases are important because they help to unravel the underlying mechanisms of diseases which may lead to novel therapies for patients. These efforts also offer rare opportunities to discover novel biological processes with major significance in biomedical research. This application is designed to explore a unique genotype-phenotype relationship based on a patient who is enrolled in the NIH Undiagnosed Disease Program (UDP). The patient harbors two compound heterozygous missense mutations in the CHML gene, with one mutant allele inherited from each parent. The patient exhibits developmental regression and neurodegeneration, including progressive cortical and white matter loss. The abnormal phenotypes are absent in the patient's siblings, who do not carry either mutation, and in their parents. In humans and other mammals, the paralogous genes CHM and CHML code for the Rab escort proteins REP-1 and REP-2, respectively. The Rab family consists of a large number of GTPases, which regulate complex membrane trafficking events. Posttranslational prenylation is required for targeting Rabs to specific subcellular membranes. REPs are essential for appropriate prenylation of Rabs. In zebrafish, there is only a single REP-coding gene, chm, and a nonsense mutation of the gene leads to degeneration of multiple organs. Extensive functional studies have been carried out on mammalian CHM orthologs. Null and missense mutations of CHM lead to degeneration of tissues in the eyes of patients with choroideremia. It has been proposed that tissues outside of the eyes in these patients, such as brain tissues, are likely protected by CHML. However, surprisingly, there are almost no functional studies of CHML orthologs despite their perceived importance until the first evidence of the impact of CHML from this UDP case. In this application, we propose to be the first group to test the related major hypothesis that CHML is an indispensable protector of brain tissues from degeneration using mouse mutations of Chml based on its high conservation with the human ortholog. In Aim 1, we will engineer Chml null alleles and the UDP patient-specific missense mutations in mice. In Aim 2, we will analyze the phenotypic consequences of compound heterozygosity of the missense mutations and the null alleles as loss-of-function controls. Phenotypic characterizations will include magnetic resonance imaging (MRI) and stereology analysis of brain structures as well as behavioral analysis of motor and cognitive functions. We will also analyze Rab prenylation in the mutant mice to explore the mechanistic link between genotypes and phenotypes. The success of this project will reveal for the first time the essential role of CHML in maintaining the integrity of the central nervous system, thereby laying the mechanistic foundation for future studies on the UDP patient, including therapeutic studies. The success of this project will also open up possibilities that CHML mutations and CHML-associated biological processes may play critical roles in other neurodegenerative disorders as well as autism spectrum disorder in which developmental regression is an important clinical feature.

描述（由应用提供）：关于罕见疾病的研究很重要，因为它们有助于揭示可能导致患者新疗法的疾病的潜在机制。这些努力还提供了难得的机会来发现在生物医学研究中具有重要意义的新型生物学过程。该应用程序旨在探索基于参加NIH未诊断疾病计划（UDP）的患者的独特基因型 - 表型关系。该患者在CHML基因中藏有两个复合杂合的错义突变，每个父母遗传了一个突变等位基因。该患者表现出发育回归和神经变性，包括进行性皮质和白质损失。在患者的兄弟姐妹中不存在任何突变和父母中的异常表型。在人类和其他哺乳动物中，分别为RAB伴随蛋白REP-1和REP-2的寄生基因CHM和CHML代码。 RAB家族由大量的GTPases组成，这些GTP酶调节复杂的膜贩运事件。将RAB靶向特定的亚细胞膜需要翻译后培养基化。 REP对于RABS的适当前化至关重要。在斑马鱼中，只有一个rep编码基因，CHM和该基因的废话突变会导致多个器官的变性。对哺乳动物CHM直系同源物进行了广泛的功能研究。 CHM的无效和错义突变导致脉络膜血症患者眼中组织变性。已经提出，这些患者的眼睛外部组织（例如脑组织）可能受到CHML的保护。然而，令人惊讶的是，尽管人们认为CHML很重要，直到第一个证据表明CHML对这种UDP案件的影响，但几乎没有对CHML直系同源物的功能研究。在此应用中，我们建议是第一个测试相关主要假设的组，即CHML是使用CHML小鼠突变基于其与人类直系同源物的高保守性，是脑组织不可或缺的保护因素。在AIM 1中，我们将在小鼠中设计CHML无效等位基因和UDP特定的错义突变。在AIM 2中，我们将分析错义突变的复合杂合性和无效控制的表型后果。表型特征将包括磁共振成像（MRI）和大脑结构的立体分析以及运动和认知功能的行为分析。我们还将分析突变小鼠中的RAB原始化，以探索基因型和表型之间的机械联系。该项目的成功将首次揭示CHML在维持中枢神经系统完整性方面的重要作用，从而为未来的UDP患者（包括治疗研究）奠定了机械基础。该项目的成功还将开辟CHML突变和与CHML相关的生物学过程可能在其他神经退行性疾病以及自闭症谱系障碍中起关键作用，其中发育回归是重要的临床特征。