Modular control of jaw tendon specification by the Nr5a2 orphan nuclear receptor

Nr5a2 孤儿核受体对颌肌腱规范的模块化控制

• 批准号: 10227394
• 负责人: Gage D Crump
• 金额: $ 6.29万
• 依托单位: UNIVERSITY OF SOUTHERN CALIFORNIA
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-03-01 至 2021-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10227394
• 关键词: Address; Binding; Biological Assay; Body part; Cartilage; Cells; Cephalic; Chromatin; Defect; Development; Enhancers; Expression Profiling; Face; Future; Genetic; Genetic Transcription; Genomics; Head; Jaw; Limb structure; Logic; Mammals; Mandible; Mesoderm; Modeling; Mus; Muscle; NR5A2 gene; Neural Crest Cell; Nuclear Orphan Receptor; Prevalence; Regenerative Medicine; Role; Signal Transduction; Skeleton; Specific qualifier value; Techniques; Temporomandibular Joint Disorders; Tendon Injuries; Tendon structure; Testing; Transgenic Organisms; Vertebral column; Zebrafish; innovation; middle ear; mutant; repaired; scleraxis; tendon development; transcription factor

Project Summary In order for the jaw to properly function, the jaw skeleton must be integrated to the underlying muscles through tendons. The prevalence of tendon injuries is high and in some cases can contribute to temporomandibular joint disorders, yet both the development and repair of tendons are largely understudied. The skeleton and tendons of the jaw are derived from cranial neural crest cells (CNCCs), in contrast to the skeleton and tendons of the fins/limbs and spine that are derived from mesoderm. Do tendons derived from different lineages depend on similar or distinct upstream signals for their specification? This proposal tests the innovative idea that tendon specification is modular, with head- and trunk-specific transcription factors initiating tendon development through head- and trunk-specific enhancers of critical tenocyte factors such as Scleraxis. By conducting single-cell RNA expression profiling of CNCC derivatives in the developing zebrafish face, we have found that expression of the nr5a2 orphan nuclear receptor marks cells along a developmental trajectory toward jaw tendon fate. Utilizing mutant and transgenic zebrafish models, we find that Nr5a2 is necessary and sufficient for specification of jaw tendon at the expense of cartilage fates. In addition, by assaying open chromatin indicative of active enhancers in CNCCs, as well as head versus trunk tenocytes, we find a number of putative head- and trunk-specific enhancers of scleraxis-a. In this proposal, we use transgenic and cutting- edge genomics techniques to test that Nr5a2 directly binds and activates jaw-specific scleraxis-a enhancers. We also use conditional genetics in mouse to test that Nr5a2 has a conserved role in specifying jaw and middle ear tendons derived from the mandibular arch in mammals. Completion of these aims will reveal the regulatory logic by which tendons are specified in different parts of the body, as well as a highly specific role for the Nr5a2 orphan nuclear receptor in promoting jaw tendon formation.

项目概要 为了使下颌正常发挥功能，下颌骨骼必须通过以下方式与下面的肌肉整合： 肌腱。肌腱损伤的发生率很高，在某些情况下可能会导致颞下颌关节紊乱 关节疾病，但肌腱的发育和修复在很大程度上还没有得到充分研究。骨架和 与骨骼和肌腱不同，下颌的肌腱源自颅神经嵴细胞（CNCC） 源自中胚层的鳍/四肢和脊柱。来自不同血统的肌腱是否取决于 其规范中相似或不同的上游信号？该提案测试了创新想法 肌腱规格是模块化的，具有头部和躯干特异性转录因子启动肌腱 通过关键肌腱细胞因子（例如 Scleraxis）的头部和躯干特异性增强剂进行发育。经过 对发育中的斑马鱼面部 CNCC 衍生物进行单细胞 RNA 表达谱分析，我们得到了 发现 nr5a2 孤儿核受体的表达标记细胞沿着发育轨迹 走向下颌肌腱的命运。利用突变体和转基因斑马鱼模型，我们发现 Nr5a2 是必需的并且 足以规范颌肌腱，但会牺牲软骨命运。此外，通过分析开放 染色质指示 CNCC 中的活性增强子，以及头部与躯干肌腱细胞，我们发现了一些 scleaxis-a 的假定头部和躯干特异性增强剂。在这个提案中，我们使用转基因和切割- 边缘基因组学技术测试 Nr5a2 直接结合并激活颌特异性巩膜增强剂。 我们还在小鼠中使用条件遗传学来测试 Nr5a2 在指定下颌和下颌骨方面具有保守作用。 中耳肌腱源自哺乳动物的下颌弓。完成这些目标将揭示 肌腱在身体不同部位的调节逻辑，以及高度特定的作用 Nr5a2 孤儿核受体促进颌肌腱形成。