Deciphering the role of Pumilio1 in two new neurological diseases

解读 Pumilio1 在两种新神经系统疾病中的作用

• 批准号: 10249566
• 负责人: Vincenzo Alessandro Gennarino
• 金额: $ 2.17万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-30 至 2024-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10249566
• 关键词: Abnormal coordination; Adult; Age; Ataxia; Award; Brain; Candidate Disease Gene; Cerebellar Ataxia; Clinical; Cognitive; Complex; Development; Disease; Evaluation; Family; Homologous Gene; Human; Knockout Mice; Lead; Maps; Motor; Mus; Mutation; Nervous System Physiology; Neurons; Parents; Patients; Phenotype; Post-Transcriptional Regulation; Proteins; Publishing; Purkinje Cells; RNA-Binding Proteins; Role; Seizures; Sum; Testing; developmental disease; early onset; early onset disorder; falls; gain of function; in vivo; loss of function; nervous system disorder

Project Summary from R01NS109858 Parent Award Little is known about the role of RNA-binding proteins in brain development or disease, but accumulating evidence indicates their involvement in neurological disorders. In fact, we found that the RNA-binding protein Pum1 is crucial for neurological function in both mice and humans. Pum1-haploinsufficient mice develop ataxia at 5 weeks of age and show Purkinje cell degeneration at 10 weeks. Pum1 knockout mice are more sick: they are born at a lower mendelian ratio, are smaller than wild-type, have early seizures, and more severe cerebellar degeneration1. We then found that mutations in human PUM1 also cause two very different diseases that parallel what we observed in mice: a mild, adult-onset pure cerebellar ataxia in patients with a mutation that reduces PUM1 levels by ~25%, and an early-onset disorder that causes several cognitive and physical delays, smaller size, motor incoordination, and seizures in patients with PUM1 mutations that reduce its levels ~40-60%2. But how do the specific mutations alter PUM1 function, aside from making it less stable? The most obvious place to look is at PUM1 targets. The only published neuronal targets are ATXN1 and E2F3, and their abundance is increased by similar amounts (~50%) in both the adult-onset ataxia and early-onset cases. The ataxia might be explained by elevated abundance of cerebellar ATXN1, but the broader phenotype of the developmental disorder must involve dysregulation of other PUM1 targets. There is, however, more of a puzzle here than is first apparent. The mildest mutation, T1035S, which reduces PUM1 levels by only 25%, is in homology domain (HD) 6; of the mutations that produce the severe, early onset phenotype, R1139W is in HD8, and R1147W is just outside this domain. Why, then, do R1139W and R1147W produce equally severe phenotypes, when only the former abolishes PUM1’s repressor activity? And why is T1035S so mild, when it also abolishes PUM1’s repressor activity? We propose that the milder disease results from target dysregulation, whereas more severe disease results when levels of PUM1 fall below a certain point (perhaps 30-40%), because its interacting partners either cannot form their normal complexes or the complexes fall apart quickly, causing loss of function of those interactors (and loss or gain of function of downstream targets). To test this two-part hypothesis, we will: 1) map the Pum1 targetome in the mouse brain as well as that of Pum2, its homolog (there may be regulatory overlap between the two proteins); 2) identify PUM1 protein interactors, and 3) study the cross-talk between Pum1 and Pum2 in mice. In sum, our recent discoveries not only define two new neurological diseases, they demonstrate that understanding the post- transcriptional regulation of disease-related proteins, like the PUF family, can lead to the identification of new candidate disease genes.

R 01 NS 109858家长奖项目摘要 关于RNA结合蛋白在大脑发育或疾病中的作用知之甚少，但积累 有证据表明他们患有神经系统疾病事实上，我们发现RNA结合蛋白 Pum 1对小鼠和人类的神经功能至关重要。Pum 1-单倍体不足小鼠发育 在5周龄时出现共济失调，在10周龄时出现浦肯野细胞变性。Pum 1基因敲除小鼠的病情更严重： 他们出生时的孟德尔比率较低，比野生型小，癫痫发作早， 小脑变性1.然后我们发现，人类β 1基因的突变也会导致两种截然不同的疾病 这与我们在小鼠中观察到的情况相似：在突变患者中， 这会降低25%的β 1水平，以及一种早发性疾病，会导致几种认知和身体疾病。 延迟，较小的尺寸，运动不协调和癫痫发作的患者中，有BIP 1突变，降低其水平 ~40- 60% 2.但是，除了使其不太稳定之外，这些特定的突变是如何改变BMP 1的功能的呢？最 最明显的地方是在101个目标。唯一公开的神经元靶点是ATXN 1和E2 F3，并且它们的 在成人发作性共济失调和早发性病例中，丰度增加相似的量（~50%）。的 共济失调可能是由小脑ATXN 1丰度升高解释的，但小脑ATXN 1的更广泛的表型可能是由小脑ATXN 1的更广泛的表型解释的。 发育障碍必然涉及其他靶点的失调。然而， 在这里比第一个明显。最温和的突变，T1035 S，它只降低了25%，是在 同源结构域（HD）6;在产生严重早发表型的突变中，R1139 W位于HD 8中， 而R1147 W正好在这个域之外。那么，为什么R1139 W和R1147 W产生同样严重的 表型，当只有前者废除的阻遏活性？为什么T1035 S如此温和，当它 也消除了BMP 1的抑制活性我们认为较轻的疾病是由目标引起的 然而，更严重的疾病的结果时，水平下降到低于某一点（也许 30-40%），因为其相互作用的伴侣不能形成正常的复合物或复合物下降 快速分离，导致这些相互作用者的功能丧失（以及下游相互作用者的功能丧失或获得）。 目标）。为了测试这两部分假设，我们将：1）绘制小鼠大脑中的Pum 1靶向组以及 Pum 2的同源物（两种蛋白质之间可能存在调控重叠）; 2）鉴定Pum 1 蛋白质相互作用，和3）研究小鼠中Pum 1和Pum 2之间的串扰。总之，我们最近 这些发现不仅定义了两种新的神经系统疾病，它们还表明， 疾病相关蛋白的转录调控，如PUF家族，可以导致新的免疫缺陷病毒的鉴定。 候选疾病基因