Hayashi Yuriko, Ono Kanako, Ono Shoichiro
Department of Pathology, Emory University, Atlanta, Georgia, 30322, USA.
Department of Cell Biology, Emory University, Atlanta, Georgia, 30322, USA.
F1000Res. 2019 Mar 12;8:279. doi: 10.12688/f1000research.18476.1. eCollection 2019.
Actin is a central component of muscle contractile apparatuses, and a number of actin mutations cause diseases in skeletal, cardiac, and smooth muscles. However, many pathogenic actin mutations have not been characterized at cell biological and physiological levels. In this study, we tested whether the nematode could be used to characterize properties of actin mutants in muscle cells . Two representative actin mutations, E99K and P164A, which cause hypertrophic cardiomyopathy in humans, are introduced in a muscle-specific actin ACT-4 as E100K and P165A, respectively. When green fluorescent protein-tagged wild-type ACT-4 (GFP-ACT-4), is transgenically expressed in muscle at low levels as compared with endogenous actin, it is incorporated into sarcomeres without disturbing normal structures. GFP-ACT-4 variants with E100K and P165A are incorporated into sarcomeres, but also accumulated in abnormal aggregates, which have not been reported for equivalent actin mutations in previous studies. Muscle contractility, as determined by worm motility, is not apparently affected by expression of ACT-4 mutants. Our results suggest that muscle is a useful model system to characterize abnormalities caused by actin mutations.
肌动蛋白是肌肉收缩装置的核心组成部分，许多肌动蛋白突变会导致骨骼肌、心肌和平滑肌疾病。然而，许多致病性肌动蛋白突变在细胞生物学和生理学水平上尚未得到表征。在本研究中，我们测试了线虫是否可用于表征肌肉细胞中肌动蛋白突变体的特性。将两种分别导致人类肥厚性心肌病的代表性肌动蛋白突变E99K和P164A，在肌肉特异性肌动蛋白ACT-4中分别作为E100K和P165A引入。当绿色荧光蛋白标记的野生型ACT-4（GFP-ACT-4）与内源性肌动蛋白相比在肌肉中低水平转基因表达时，它被整合到肌节中而不会干扰正常结构。带有E100K和P165A的GFP-ACT-4变体被整合到肌节中，但也会在异常聚集体中积累，这在先前研究中对于等效的肌动蛋白突变尚未有报道。由蠕虫运动性测定的肌肉收缩力显然不受ACT-4突变体表达的影响。我们的结果表明，线虫肌肉是表征肌动蛋白突变引起的异常的有用模型系统。
