Specific isomyosin proportions in hyperexcitable and physiologically denervated mouse muscle.
We show here, by high resolution sodium dodecyl sulfate gel electrophoresis, that the proportions of myosin heavy chain (MyHC) isoforms of mouse muscles are specifically shifted by hereditary neuromuscular diseases. In wild-type and dystrophic MDX anterior tibial muscle (TA) about 60% of the MyHC is IIB, 30% IIX, at most 10% IIA and <2% type I (slow). In myotonic fast muscles, hyperexcitability leads to a drastic reduction of MyHC IIB which is compensated by IIA. Slow muscles, like soleus and diaphragm, were only marginally changed by myotonia. The MyHC pattern of TA of spinal muscular atrophy (SMA) 'wobbler' mice is shifted to a faster phenotype, with nearly 90% IIB. In the SMA mutant 'muscle deficient', all four adult isomyosins are expressed in the TA. These findings may be relevant for the future diagnosis of neurological disorders both in mouse disease models and in human patients.
Agbulut
Onnik
O
INSERM U572, Hôpital Lariboisière, 41, Bd de la Chapelle, 75010 Paris, France.
Noirez
Philippe
P
Butler-Browne
Gillian
G
Jockusch
Harald
H
D000818:Animals; D004591:Electrophoresis, Polyacrylamide Gel; D051379:Mice; D008817:Mice, Mutant Strains; D009121:Muscle Denervation; D018656:Muscle Fibers, Fast-Twitch / Q000737:chemistry; D018657:Muscle Fibers, Slow-Twitch / Q000737:chemistry; D018482:Muscle, Skeletal / Q000737:chemistry* / Q000294:innervation / Q000473:pathology; D018995:Myosin Heavy Chains / Q000032:analysis*; D009468:Neuromuscular Diseases / Q000175:diagnosis / Q000235:genetics / Q000378:metabolism*; D020033:Protein Isoforms / Q000032:analysis*
D020033:Protein Isoforms; D018995:Myosin Heavy Chains