SPEG is Critical in Skeletal Muscle Development and Function

SPEG 对骨骼肌发育和功能至关重要

• 批准号: 9301482
• 负责人: PANKAJ B AGRAWAL
• 金额: $ 38.94万
• 依托单位: BOSTON CHILDREN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-14 至 2020-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9301482
• 关键词: Affect; Apoptosis; Architecture; Birth; Breathing; Cell Differentiation process; Cell Nucleus; Cell model; Cells; Centronuclear myopathy; Cessation of life; Chromosome Mapping; Coupling; Data; Defect; Desmin; Diagnosis; Differentiation and Growth; Dilated Cardiomyopathy; Disease; Family; Frequencies; Functional disorder; Future; Gene Mutation; Gene Proteins; Genes; Genetic; Genetic Transcription; Genome; Goals; Heart; Hereditary Disease; Human; Immunofluorescence Immunologic; Individual; Intermediate Filaments; Knock-out; Knockout Mice; Life; Lipids; Locus Control Region; Mammals; Mitochondria; Molecular; Mus; Muscle; Muscle Development; Muscle Fibers; Muscle function; Muscle hypotonia; Mutation; Myocardium; Myopathy; Patients; Phenotype; Phosphoric Monoester Hydrolases; Protein Deficiency; Proteins; Regulation; Resolution; Role; Sarcoplasmic Reticulum; Skeletal Muscle; Structure; Tamoxifen; Therapeutic; Work; X-linked myotubular myopathy; Yeasts; congenital myopathy; exome sequencing; feeding; insight; mouse model; myotubularin; postnatal; proband; prospective; protein function; public health relevance; repaired; skeletal; skeletal muscle growth; yeast two hybrid system

 DESCRIPTION (provided by applicant): Congenital myopathies (CM) are a heterogeneous group of skeletal muscle disorders that manifest as hypotonia as well as breathing and feeding difficulties early in life, and can often be fatal. Centronuclear myopathy (CNM) is a common CM subtype characterized by the mislocalization of nuclei from the periphery to the center of myofibers. X-linked myotubular myopathy, the most frequent and severe form of CNM, is caused by MTM1 mutations. Myotubularin or MTM1 is a lipid phosphatase, and little is known about its interacting partners. To determine MTM1-interacting proteins, we conducted a yeast two-hybrid screen and found striated preferentially expressed gene (SPEG) to be an interacting partner. Concurrently, whole exome sequencing to determine genetic basis of CNM revealed recessive SPEG mutations in probands from three unrelated CNM families. Two of the three were also diagnosed with dilated cardiomyopathy (DCM), one of which had spontaneous resolution by a year. Our results suggest that mutations in SPEG cause a CNM phenotype, but the underlying basis for skeletal muscle dysfunction is unknown. Knocking out Speg in a mouse model has been associated with severe DCM, an increased number of central nuclei, and death by postnatal day two. SPEG and desmin genes are tandemly arrayed on the genome, and a common locus control region in mammals regulates their expression. Immunofluorescence studies have shown that SPEG localizes with the terminal cisternae of the sarcoplasmic reticulum (SR). We propose that SPEG may maintain terminal SR structure for efficient excitation-contraction coupling. In Aim 1, we will decipher the molecular mechanisms responsible for poor skeletal muscle function associated with lack of SPEG and its differential role in skeletal and cardiac muscles. In Aim 2, we will investigate SPEG's involvement in skeletal muscle growth and differentiation, with special focus on central nucleation. In Aim 3, we will determine the relationship between SPEG, MTM1, and desmin. The overall goals of the proposal are to understand how lack of SPEG affects muscle function, its role in muscle growth and differentiation, and relationship with MTM1 and desmin. When completed, this work will provide clear insights into the molecular functions of SPEG in skeletal muscle, and how its deficiency causes CNM. The findings will help determine therapeutic approaches against such devastating muscle diseases.

 描述（由申请人提供）：先天性肌病（CM）是一组异质性骨骼肌疾病，在生命早期表现为张力减退以及呼吸和喂养困难，通常可能是致命的。中枢性肌病（CNM）是一种常见的CM亚型，其特征是肌纤维的核从外周到中心的错误定位。X连锁肌管性肌病是最常见和最严重的CNM形式，由MTM1突变引起。肌管蛋白或MTM1是一种脂质磷酸酶，对其相互作用伴侣知之甚少。为了确定MTM1相互作用蛋白，我们进行了酵母双杂交筛选，发现条纹优先表达基因（SPEG）是一个相互作用的伴侣。同时，全外显子测序，以确定CNM的遗传基础，发现隐性SPEG突变的先证者从三个无关的CNM家庭。三人中的两人也被诊断为扩张型心肌病（DCM），其中一人在一年内自发消退。我们的研究结果表明，SPEG突变导致CNM表型，但骨骼肌功能障碍的基础尚不清楚。在小鼠模型中敲除Speg与严重DCM、中央核数目增加和出生后第二天死亡有关。SPEG和结蛋白基因在基因组上串联排列，哺乳动物中的共同基因座控制区调节它们的表达。免疫荧光研究表明，SPEG定位于肌浆网（SR）的末端池。我们建议，SPEG可能保持终端SR结构有效的兴奋收缩耦合。在目标1中，我们将破译与缺乏SPEG相关的骨骼肌功能差的分子机制及其在骨骼肌和心肌中的差异作用。在目标2中，我们将研究SPEG参与骨骼肌生长和分化，特别关注中央成核。在目标3中，我们将确定SPEG，MTM1和结蛋白之间的关系。该提案的总体目标是了解缺乏SPEG如何影响肌肉功能，其在肌肉生长和分化中的作用，以及与MTM1和结蛋白的关系。完成后，这项工作将提供明确的见解SPEG在骨骼肌中的分子功能，以及它的缺乏如何导致CNM。这些发现将有助于确定针对这种破坏性肌肉疾病的治疗方法。