SMCHD1 Pathways as Candidate Targets for FSHD

项目摘要 面肩肱营养不良（FSHD）影响约1/10，000的人，由减少的 骨骼肌中DUX 4逆转录基因的表观遗传抑制和随后的DUX 4错误表达 肌肉.随着SMCHD 1介导的D4 Z4基因座表观遗传抑制的增加，DUX 4基因沉默 在FSHD 1和FSHD 2肌细胞中，该应用将采用直接的分子生物学方法， 确定SMCHD 1复合物的多样性以及每个组分在建立和 维持D4 Z4处的抑制性染色质结构并阻止骨骼肌中DUX 4的表达， 肌肉.广泛和长期的目标是确定SMCHD的功能组件1 D4 Z4基因座的复合物作为未来治疗的基础，旨在增加表观遗传 镇压主要的假设是SMCHD 1形成不同的相互作用，这取决于 翻译修饰、染色质缔合和细胞的发育状态，并且 理解不同复合物的功能作用将为我们提供简单的简化模型， 测试候选干预措施。目的1将确定与SMCHD 1复合的蛋白质， D4 Z4基因座及其功能意义、染色质关联和SUMO依赖性。目标2将 确定基因组中常染色体单拷贝位点SMCHD 1复合物的组成 与D4 Z4的重复区域和亚结构域相比。目标3将确定以下方面的相对作用： SMCHD 1复合物组分在表观遗传修饰的建立和维持中的作用 在干细胞重编程和分化过程中。总之，这些目标将使 SMCHD 1复合物的组分及其在D4 Z4表观遗传抑制中的功能作用，以及 为设计干预措施以抑制DUX 4表达提供了新的机会， FSHD。

PROJECT SUMMARY Facioscapulohumeral dystrophy (FSHD) affects ~1/10,000 people and is caused by decreased epigenetic repression of the DUX4 retrogene with subsequent mis-expression of DUX4 in skeletal muscle. As increasing the SMCHD1-mediated epigenetic repression at the D4Z4 locus silences DUX4 in FSHD1 and FSHD2 muscle cells, this application will take a direct molecular biology approach to identify the diversity of SMCHD1 complexes and the role of each component in establishing and maintaining repressive chromatin structure at the D4Z4 and preventing DUX4 expression in skeletal muscle. The broad and long-term goal is to determine the functional components of the SMCHD1 complexes at the D4Z4 locus as a basis for future therapies directed at increasing epigenetic repression. The major hypothesis is that SMCHD1 forms different interactions depending on post- translational modification, chromatin association, and developmental state of the cell, and that understanding the functional roles of the different complexes will provide simple reductionist models for testing candidate interventions. Aim 1 will determine the proteins complexed with SMCHD1 at the D4Z4 locus and their functional significance, chromatin association, and SUMO dependence. Aim 2 will determine the composition of SMCHD1 complexes at autosomal single copy loci in the genome compared to repetitive regions and to subdomains of the D4Z4. Aim 3 will identify the relative roles of SMCHD1 complex components in the establishment and maintenance of epigenetic modifications during stem cell reprogramming and differentiation. Together, these aims will add clarity to the components of SMCHD1 complexes and their functional roles in D4Z4 epigenetic repression, and provide new opportunities to design interventions to suppress DUX4 expression as a treatment for FSHD.