Ronin (Thap11) in Neural Crest Cell Development

项目概要/摘要 神经嵴细胞（NCC）是一种短暂的、多能的、迁移性的胚胎细胞群， 形成了包括颅面骨骼在内的一系列组织破坏细胞和分子 驱动NCC特化、迁移和/或分化的机制导致代表性的颅面疾病， 大约三分之一的婴儿出生时有先天缺陷。因此，我们的长期目标是确定NCC基因 监管网络，赋予这种专门的属性。在本建议中，我们将确定 转录因子RONIN（THAP 11）通过直接转录调节 钴胺素（维生素B12）辅酶生物合成。我们还将定义RONIN失调对 一种新发现的人类综合症cblX的病理生理学。在初步研究中，我们发现罗宁是 在整个发育中的NCC群体中表达，并且Ronin的条件性敲除（CKO）引起NCC- 衍生的颅面骨骼发育不全，而不严重改变心脏、周围神经 系统和肠系统。这些数据表明，骨软骨形成NCC谱系是唯一敏感的， 失去罗尼我们最近还确定Mmachc作为RONIN的直接转录靶点。MMACHC调节 钴胺素辅酶的产生和人类MMAHC的突变导致甲基丙二酸血症 和命名为cblC的同型胱氨酸尿症。CblC是细胞内钴胺素代谢最常见的先天性缺陷 并且通常表现为主要影响血液和神经发育的多系统疾病。 还有颅面畸形的其他报告。此外，RONIN及其辅因子HCFC 1的突变也是 最近在cblC样综合征cblX中发现。这些数据让我们假设颅面 在Ronin突变体中观察到的缺陷是脑内钴胺素代谢途径失调的结果。 净捐助国。为了测试这一点，我们将进行一系列的浪人功能丧失，遗传相互作用和救援实验。 我们还将确定野生型和突变型NCC内钴胺素代谢途径的功能。 在成功完成这些目标后，我们期望已经确定了一个转录机制， 钴胺素代谢到NCC分化成颅面骨骼。更好地了解NCC 发展可能最终为更有效的再生医学策略提供信息，并导致新的治疗方法 颅面缺损的治疗目标

PROJECT SUMMARY/ABSTRACT Neural crest cells (NCCs) are a transient, multipotent, migratory population of embryonic cells, which give rise to a remarkable array of tissues including the craniofacial skeleton. Disruption of the cellular and molecular mechanisms driving NCC specification, migration, and/or differentiation causes craniofacial disorders representing approximately one-third of all babies born with birth defects. Thus, our long-term goal is to define the NCC gene regulatory network that confers such specialized properties. In this proposal, we will determine whether the transcription factor RONIN (THAP11) directs cranial NCC development by direct transcriptional regulation of cobalamin (vitamin B12) coenzyme biosynthesis. We will also define the contribution of RONIN misregulation to the pathophysiology of a newly discovered human syndrome called cblX. In preliminary studies, we found that Ronin is expressed throughout the developing NCC population and that conditional knockout (CKO) of Ronin caused NCC- derived craniofacial skeletal agenesis without grossly altering other NCC derivatives in the heart, peripheral nervous system and enteric system. These data indicate that the osteochondrogenic NCC lineage is uniquely sensitive to loss of Ronin. We also recently identified Mmachc as a direct transcriptional target of RONIN. MMACHC regulates cobalamin coenzyme production and human mutations in MMACHC cause a combined methylmalonic acidemia and homocystinuria designated cblC. CblC is the most common inborn error of intracellular cobalamin metabolism and often presents as a multisystem disease predominantly impacting hematologic and neurologic development. There are additional reports of craniofacial dysmorphias. Also, mutations in RONIN and its co-factor HCFC1 were recently identified in a cblC-like syndrome, cblX. These data have led to us to hypothesize that the craniofacial defects observed in Ronin mutants are a result of dysregulation of the cobalamin metabolic pathway in cranial NCCs. To test this, we will perform a series of Ronin loss-of-function, genetic interaction, and rescue experiments. We will also determine the functionality of the cobalamin metabolic pathway within wild type and mutant NCCs. Upon successful completion of these aims, we expect to have identified a transcriptional mechanism that links cobalamin metabolism to NCC differentiation into the craniofacial skeleton. This better understanding of NCC development may ultimately inform more efficacious regenerative medicine strategies and lead to new therapeutic targets for craniofacial defects.