Calpain 3 mRNA expression in mice after denervation and during muscle regeneration.
Lack of functional calpain 3 in humans is a cause of limb girdle muscular dystrophy, but the function(s) of calpain 3 remain(s) unknown. Special muscle conditions in which calpain 3 is downregulated could yield valuable clues to the understanding of its function(s). We monitored calpain 3 mRNA amounts by quantitative RT-PCR and compared them with those of alpha-skeletal actin mRNA in mouse leg muscles for different types of denervation and muscle injury. Intact muscle denervation reduced calpain 3 mRNA expression by a factor of 5 to 10, while alpha-skeletal actin mRNA was reduced in a slower and less extensive manner. Muscle injury (denervation-devascularization), which leads to muscle degeneration and regeneration, induced a 20-fold decrease in the mRNA level of both calpain 3 and alpha-skeletal actin. Furthermore, whereas in normal muscle and intact denervated muscle, the full-length transcript is the major calpain 3 mRNA, in injured muscle, isoforms lacking exon 6 are predominant during the early regeneration process. These data suggest that muscle condition determines the specific calpain 3 isoform pattern of expression and that calpain 3 expression is downregulated by denervation.
Stockholm
D
D
Généthon, CNRS URA 1922-1923, 1 bis rue de l'Internationale, BP 60, 91002 Evry, France.
Herasse
M
M
Marchand
S
S
Praud
C
C
Roudaut
C
C
Richard
I
I
Sebille
A
A
Beckmann
J S
JS
D000199:Actins / Q000235:genetics; D017398:Alternative Splicing / Q000502:physiology; D000818:Animals; D017209:Apoptosis / Q000502:physiology; D002154:Calpain / Q000235:genetics*; D017931:DNA Primers; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D008297:Male; D051379:Mice; D009121:Muscle Denervation; D018485:Muscle Fibers, Skeletal / Q000201:enzymology / Q000473:pathology; D009124:Muscle Proteins; D018482:Muscle, Skeletal / Q000473:pathology / Q000502:physiology*; D012333:RNA, Messenger / Q000032:analysis; D012038:Regeneration / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012584:Sciatic Nerve / Q000502:physiology / Q000601:surgery
D000199:Actins; D017931:DNA Primers; D009124:Muscle Proteins; D012333:RNA, Messenger; D002154:Calpain; C491373:Capn3 protein, mouse