CYPHER, Z LINE PROTEIN

该子项目是利用NIH/NCRR资助的中心赠款提供的资源的许多研究子项目之一。子项目和研究者（PI）可能从另一个NIH来源获得主要资金，因此可以在其他CRISP条目中表示。所列机构为中心，不一定是研究者所在机构。Cypher基因敲除小鼠表现出严重的先天性肌病，并在出生后死于多个横纹肌的功能衰竭。使用IVEM对突变体的横纹肌进行的检查显示，Cypher不是肌角化或Z线组装所需的，而是在肌肉功能期间维持Z线所需的。目前正在编写一份关于Cypher的手稿，这是一种Z线特异性蛋白质，包括高放大率电子显微镜断层扫描。 基于包含骨骼或心脏特异性结构域，Cypher的六种亚型可分为骨骼或心脏特异性类别。短和长同种型共享N-末端PDZ结构域，但三个C-末端LIM结构域是长同种型所特有的。为了研究剪接变体在体内的功能，我们通过用编码短或长骨骼肌同种型的cDNA替换内源性Cypher基因来进行Cypher无效突变体的拯救实验。与Cypher缺失小鼠相反，仅表达短或长骨骼肌特异性同种型的小鼠的百分比可以存活到至少一岁。尽管存活的小鼠表现出肌肉病理学，但这些结果表明，任一同种型都足以挽救与不存在Cypher相关的致死性。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Cypher knockout mice display a severe form of congenital myopathy and die postnatally from functional failure in multiple striated muscles. Examination of striated muscle from the mutants using IVEM revealed that Cypher is not required for sarcomerogenesis or Z-line assembly, but rather is required for maintenance of the Z-line during muscle function. A manuscript on Cypher, a Z-line specific protein including high magnification electron microscopic tomography is now being prepared. The six isoforms of Cypher can be divided into skeletal or cardiac specific classes, based on the inclusion of skeletal or cardiac specific domains. Short and long isoforms share an N-terminal PDZ domain, but the three C-terminal LIM domains are unique to long isoforms. To investigate the function of splice variants in vivo, we have performed a rescue experiment of the Cypher null mutant by replacing the endogenous Cypher gene with cDNAs encoding either a short or long skeletal muscle isoform. In contrast to Cypher null mice, a percentage of mice that express only a short or a long skeletal muscle specific isoform can survive to at least one year of age. Although surviving mice exhibit muscle pathology, these results suggest that either isoform is sufficient to rescue the lethality associated with absence of Cypher.