The Wellcome Lecture, 1988 - Muscular dystrophy: a time of hope

Duchenne muscular dystrophy (DMD) and its less severe allele Becker muscular dystrophy (BMD) are progressive muscle-wasting disorders of children, DMD is characterized by rapid loss of muscle fibres and the ensuing weakness results in lost mobility and eventual premature death. Despite extensive research for many years, the basic underlying biochemical defect has remained elusive. Here I try to demonstrate how the powerful techniques of molecular genetics can be used to gain a further understanding of this particular disorder and how, in principle, the techniques can be applied to the other 3000 human genetic disorders that are so far uncharacterized. Once the chromosomal map position of DMD was established, the locus that was being disrupted by mutation could be identified and the encoded protein product predicted from the nucleotide sequence of the RNA transcript. This has led to the identification of a previously uncharacterized protein named dystrophin. As the normal function of dystrophin is determined, more accurate clinical diagnosis of DMD and BMD should result and potential approaches to therapy should be designed.

Life ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 978
Author(s):  
Emma Tabe Eko Niba ◽  
Hiroyuki Awano ◽  
Tomoko Lee ◽  
Yasuhiro Takeshima ◽  
Masakazu Shinohara ◽  
...  

Duchenne muscular dystrophy (DMD) is a fatal muscle wasting disease caused by deficiency in dystrophin, a protein product encoded by the DMD gene. Mitochondrial dysfunction is now attracting much attention as a central player in DMD pathology. However, dystrophin has never been explored in human mitochondria. Here, we analyzed dystrophin in cDNAs and mitochondrial fractions of human cells. Mitochondrial fraction was obtained using a magnetic-associated cell sorting (MACS) technology. Dystrophin was analyzed by reverse transcription (RT)-PCR and western blotting using an antibody against the dystrophin C-terminal. In isolated mitochondrial fraction from HEK293 cells, dystrophin was revealed as a band corresponding to Dp71b and Dp71ab subisoforms. Additionally, in mitochondria from HeLa, SH-SY5Y, CCL-136 and HepG2 cells, signals for Dp71b and Dp71ab were revealed as well. Concomitantly, dystrophin mRNAs encoding Dp71b and Dp71ab were disclosed by RT-PCR in these cells. Primary cultured myocytes from three dystrophinopathy patients showed various levels of mitochondrial Dp71 expression. Coherently, levels of mRNA were different in all cells reflecting the protein content, which indicated predominant accumulation of Dp71. Dystrophin was demonstrated to be localized to human mitochondrial fraction, specifically as Dp71 subisoforms. Myocytes derived from dystrophinopathy patients manifested different levels of mitochondrial Dp71, with higher expression revealed in myocytes from Becker muscular dystrophy (BMD) patient-derived myocytes.


2009 ◽  
Vol 31 (6) ◽  
pp. 600-604
Author(s):  
Qian WANG ◽  
Chun-Lian JIN ◽  
Chang-Kun LIN ◽  
Wan-Ting CUI ◽  
Hong-Wei MA ◽  
...  

2021 ◽  
Vol 22 (10) ◽  
pp. 5276
Author(s):  
Coralie Croissant ◽  
Romain Carmeille ◽  
Charlotte Brévart ◽  
Anthony Bouter

Muscular dystrophies constitute a group of genetic disorders that cause weakness and progressive loss of skeletal muscle mass. Among them, Miyoshi muscular dystrophy 1 (MMD1), limb girdle muscular dystrophy type R2 (LGMDR2/2B), and LGMDR12 (2L) are characterized by mutation in gene encoding key membrane-repair protein, which leads to severe dysfunctions in sarcolemma repair. Cell membrane disruption is a physiological event induced by mechanical stress, such as muscle contraction and stretching. Like many eukaryotic cells, muscle fibers possess a protein machinery ensuring fast resealing of damaged plasma membrane. Members of the annexins A (ANXA) family belong to this protein machinery. ANXA are small soluble proteins, twelve in number in humans, which share the property of binding to membranes exposing negatively-charged phospholipids in the presence of calcium (Ca2+). Many ANXA have been reported to participate in membrane repair of varied cell types and species, including human skeletal muscle cells in which they may play a collective role in protection and repair of the sarcolemma. Here, we discuss the participation of ANXA in membrane repair of healthy skeletal muscle cells and how dysregulation of ANXA expression may impact the clinical severity of muscular dystrophies.


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