Ronin (Thap11) in Neural Crest Cell Development

项目摘要/摘要 神经脊细胞(NCC)是一种瞬时的、多潜能的、可迁移的胚胎细胞群体，它提供了 形成了一系列引人注目的组织，包括头面部骨骼。细胞和分子的破坏 驱动NCC规范、迁移和/或分化的机制导致头面部疾病，表现为 大约三分之一的婴儿出生时就有先天缺陷。因此，我们的长期目标是定义NCC基因 授予这种特殊性质的监管网络。在这项提案中，我们将确定是否 转录因子罗宁(THAP11)通过直接转录调控脑神经细胞癌的发育 钴胺(维生素B12)辅酶生物合成。我们还将定义罗宁不当监管对 一种新发现的名为cblX的人类综合征的病理生理学。在初步研究中，我们发现罗宁是 在发育中的NCC人群中表达，并且Ronin的条件基因敲除(CKO)导致NCC- 衍生性颅面部骨骼发育不全不明显改变心脏、周围神经的其他NCC衍生物 肠道系统和肠道系统。这些数据表明，骨软骨性NCC谱系对 失去罗宁。最近，我们还发现MMACHC是罗宁的一个直接转录靶点。MMACHC规定 钴胺辅酶的产生和MMACHC的人类突变导致混合性甲基丙二酸血症 同型半胱氨酸尿症命名为cblC。CBLC是细胞内钴胺代谢最常见的先天错误 通常表现为一种主要影响血液和神经发育的多系统疾病。 还有更多关于头面部变形症的报告。此外，罗宁及其辅助因子HCFC1的突变是 最近发现了一种类似cblC的综合征，cblX。这些数据让我们假设头面部 在罗宁突变体中观察到的缺陷是脑部钴胺代谢途径失调的结果 NCCS。为了测试这一点，我们将进行一系列罗宁功能丧失、遗传交互作用和抢救实验。 我们还将确定钴胺代谢途径在野生型和突变型NCC中的功能。 在成功完成这些目标后，我们预计已经确定了一种转录机制，将 钴胺代谢向NCC分化为头面部骨骼。这对NCC有更好的理解 发展最终可能为更有效的再生医学策略提供信息，并导致新的治疗方法 头面部缺陷的目标。

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.