Dynamic assembly properties of nonmuscle myosin II isoforms revealed by combination of fluorescence correlation spectroscopy and fluorescence cross-correlation spectroscopy

Myosin II molecules assemble into filaments through their C-terminal rod region, and are responsible for several cellular motile activities. Three isoforms of nonmuscle myosin II (IIA, IIB and IIC) are expressed in mammalian cells. However, little is known regarding the isoform composition in filaments. To obtain new insight into the assembly properties of myosin II isoforms, especially regarding the isoform composition in filaments, we performed a combination analysis of fluorescence correlation spectroscopy (FCS) and fluorescence cross-correlation spectroscopy (FCCS), which enables us to acquire information on both the interaction and the size of each molecule simultaneously. Using C-terminal rod fragments of IIA and IIB (ARF296 and BRF305) labelled with different fluorescent probes, we demonstrated that hetero-assemblies were formed from a mixture of ARF296 and BRF305, and that dynamic exchange of rod fragments occurred between pre-formed homo-assemblies of each isoform in an isoform-independent manner. We also showed that Mts1 (S100A4) specifically stripped ARF296 away from the hetero-assemblies, and consequently, homo-assemblies of BRF305 were formed. These results suggest that IIA and IIB can form hetero-filaments in an isoform-independent manner, and that a factor like Mts1 can remove one isoform from the hetero-filament, resulting in a formation of homo-filaments consisting of another isoform

Comprehensive analysis for genetic diagnosis of Dystrophinopathies in Japan

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Comprehensive analysis for genetic diagnosis of Dystrophinopathies in Japan

Abstract Background Duchenne muscular dystrophy (DMD) is the most common disease in children caused by mutations in the DMD gene, and DMD and Becker muscular dystrophy (BMD) are collectively called dystrophinopathies. Dystrophinopathies show a complex mutation spectrum. The importance of mutation databases, with clinical phenotypes and protein studies of patients, is increasingly recognized as a reference for genetic diagnosis and for the development of gene therapy. Methods We used the data from the Japanese Registry of Muscular Dystrophy (Remudy) compiled during from July 2009 to March 2017, and reviewed 1497 patients with dystrophinopathies. Results The spectrum of identified mutations contained exon deletions (61%), exon duplications (13%), nonsense mutations (13%), small deletions (5%), small insertions (3%), splice-site mutations (4%), and missense mutations (1%). Exon deletions were found most frequently in the central hot spot region between exons 45–52 (42%), and most duplications were detected in the proximal hot spot region between exons 3–25 (47%). In the 371 patients harboring a small mutation, 194 mutations were reported and 187 mutations were unreported. Conclusions We report the largest dystrophinopathies mutation dataset in Japan from a national patient registry, “Remudy”. This dataset provides a useful reference to support the genetic diagnosis and treatment of dystrophinopathy

Additional file 1: Table S1. of Comprehensive analysis for genetic diagnosis of Dystrophinopathies in Japan

Clinical and dystrophin immunostaining in the patients with a small mutation. Table S2. Patients with nonsense mutation and faint&patchy dystrophin staining. (PDF 286 kb