Investigating how Mylpf-regulated sarcomere formation influences limb skeletal development

研究 Mylpf 调节的肌节形成如何影响肢体骨骼发育

• 批准号: 10437165
• 负责人: Jared Coffin Talbot
• 金额: $ 43.34万
• 依托单位: UNIVERSITY OF MAINE ORONO
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10437165
• 关键词: Actins; Affect; Alleles; Arthrogryposis; Binding Proteins; Birth; Cartilage; Chemicals; Congenital Abnormality; Congenital clubfoot; Contracts; Contracture; Defect; Deformity; Development; Disease; Disease model; Distal; Embryo; Embryonic Development; Fishes; Genes; Hand; Head; Heat-Shock Response; Human; Image; Imaging Device; Impairment; Joints; Label; Larva; Lead; Limb structure; Link; Live Birth; Modeling; Movement; Muscle; Muscle Contraction; Muscle Development; Muscle Fibers; Muscle function; Musculoskeletal; Musculoskeletal Development; Musculoskeletal Diseases; Mutation; Myosin ATPase; Myosin Heavy Chains; Myosin Light Chains; Myosin Type II; Nonmuscle Myosin Type IIA; Operative Surgical Procedures; Paralysed; Patients; Phenotype; Proteins; Role; Sarcomeres; Skeletal Development; Skeleton; Stigmatization; Testing; Thick; Thick Filament; Thin Filament; Transgenic Organisms; Variant; Work; Zebrafish; arthropathies; base; chronic pain; foot; genetic variant; human disease; human model; in utero; inhibitor; innovation; joint formation; motor impairment; mutant; prevent; restoration; skeletal; unpublished works

Investigating how Mylpf-regulated sarcomere formation influences limb skeletal development In arthrogryposis, babies are born with at least two limbs with hand or foot showing contractures; it most commonly manifests as clubfoot, and it is found in roughly 1 in 4000 live births. Arthrogryposis causes impaired movement and can require many surgeries through a lifetime to correct. The disease is characterized by skeletal joint defects, but it is caused by impaired muscle movement in utero. We recently found that the muscle-expressed gene Mylpf is vital not only to normal actin movement, but also for muscle fiber integrity and that variants in human MYLPF cause Distal Arthrogryposis Type 1 (DA1). Mylpf protein binds to the myosin heavy chain near head region which moves actin during muscle contraction. We discovered that zebrafish mylpfa mutant larvae display a phenotype consistent with DA1, including impaired myosin activity, reduced muscle force overall, and complete fin paralysis. Surprisingly, we find that Mylpf function is needed not only for normal contraction, but also for the assembly of actin and myosin into the fundamental unit of muscle, called sarcomeres. In unpublished work we find that sarcomeres form poorly in mylpfa mutants, lacking one of two Mylpf genes, and are completely absent in mylpfa;mylpfb double mutants, which lack all Mylpf function. We hypothesize that Mylpf function prevents distal arthrogryposis by promoting association of sarcomeric components during the critical window of embryonic development when limb joints are forming. To test this hypothesis, we will (Aim 1) investigate the role of Mylpf in sarcomere assembly, (Aim 2a) investigate how the human MYLPF gene variants cause this musculo-skeletal disease, and (Aim 2b) when the skeletal defects can be corrected.

研究Mylpf调节的肌节形成如何影响肢体骨骼发育 在关节畸形症中，婴儿出生时至少有两条肢体，手部或脚部出现痉挛；大多数 通常表现为马蹄内翻足，大约每4000名活产儿中就有一人患有马蹄内翻足。关节畸形导致功能受损 运动，一生可能需要多次手术才能纠正。这种疾病的特点是 骨骼关节缺陷，但它是由子宫内肌肉运动受损引起的。我们最近发现， 肌肉表达基因Mylpf不仅对正常的肌动蛋白运动至关重要，而且对肌肉纤维的完整性和 人类多发性肌萎缩侧索硬化症变异导致远端关节紊乱病1型(DA1)。Mylpf蛋白与肌球蛋白结合 头部附近的重链，在肌肉收缩时移动肌动蛋白。我们发现斑马鱼 Mylpfa突变幼虫表现出与DA1一致的表型，包括肌球蛋白活性受损，减少 全身肌肉力量，以及完全的鳍瘫痪。令人惊讶的是，我们发现Mylpf函数不仅用于 正常收缩，还用于将肌动蛋白和肌球蛋白组装成肌肉的基本单位，称为 肉尾蛇。在未发表的工作中，我们发现在mylpfa突变体中肌节的形成很差，缺少两种之一。 Mylpf基因，并且在缺乏全部Mylpf功能的Mylpfb双突变体中完全缺失。我们 假设Mylpf功能通过促进肌节的联合来预防远端关节僵硬 当四肢关节形成时，胚胎发育的关键窗口中的组件。为了测试这一点 假设，我们将(目标1)调查Mylpf在肌节组装中的作用，(目标2a)调查如何 人类MYLPF基因变异导致这种肌肉骨骼疾病，并且(目标2b)当骨骼缺陷可以 被纠正了。