|
|
||||||||
Department of Cellular and Molecular Medicine, Faculty of Medicine, and Centre for Neuromuscular Disease, University of Ottawa, Ottawa, Ontario, Canada K1H 8M5
In addition to showing differences in the levels of contractile proteins and metabolic enzymes, fast and slow muscles also differ in their expression profile of structural and synaptic proteins. Because utrophin is a structural protein expressed at the neuromuscular junction, we hypothesize that its expression may be different between fast and slow muscles. Western blots showed that, compared with fast extensor digitorum longus (EDL) muscles, slow soleus muscles contain significantly more utrophin. Quantitative RT-PCR revealed that this difference is accompanied by a parallel increase in the expression of utrophin transcripts. Interestingly, the higher levels of utrophin and its mRNA appear to occur in extrasynaptic regions of muscle fibers as shown by immunofluorescence and in situ hybridization experiments. Furthermore, nuclear run-on assays showed that the rate of transcription of the utrophin gene was nearly identical between EDL and soleus muscles, indicating that increased mRNA stability accounts for the higher levels of utrophin in slow muscles. Direct plasmid injections of reporter gene constructs showed that cis-acting elements contained within the utrophin 3'-untranslated region (3'-UTR) confer greater stability to chimeric LacZ transcripts in soleus muscles. Finally, we observed a clear difference between EDL and soleus muscles in the abundance of RNA-binding proteins interacting with the utrophin 3'-UTR. Together, these findings highlight the contribution of posttranscriptional events in regulating the expression of utrophin in muscle.
Duchenne muscular dystrophy; synaptic proteins; messenger ribonucleic acid stability; ribonucleic acid-binding proteins; neuromuscular junction
This article has been cited by other articles:
![]() |
J. V. Chakkalakal, P. Miura, G. Belanger, R. N. Michel, and B. J. Jasmin Modulation of utrophin A mRNA stability in fast versus slow muscles via an AU-rich element and calcineurin signaling Nucleic Acids Res., February 11, 2008; 36(3): 826 - 838. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. V. Chakkalakal, S. A. Michel, E. R. Chin, R. N. Michel, and B. J. Jasmin Targeted inhibition of Ca2+/calmodulin signaling exacerbates the dystrophic phenotype in mdx mouse muscle Hum. Mol. Genet., May 1, 2006; 15(9): 1423 - 1435. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. M. Judge, M. Haraguchiln, and J. S. Chamberlain Dissecting the signaling and mechanical functions of the dystrophin-glycoprotein complex J. Cell Sci., April 15, 2006; 119(8): 1537 - 1546. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. M. Angus, J. V. Chakkalakal, A. Mejat, J. K. Eibl, G. Belanger, L. A. Megeney, E. R. Chin, L. Schaeffer, R. N. Michel, and B. J. Jasmin Calcineurin-NFAT signaling, together with GABP and peroxisome PGC-1{alpha}, drives utrophin gene expression at the neuromuscular junction Am J Physiol Cell Physiol, October 1, 2005; 289(4): C908 - C917. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. Miura, J. Thompson, J. V. Chakkalakal, M. Holcik, and B. J. Jasmin The Utrophin A 5'-Untranslated Region Confers Internal Ribosome Entry Site-mediated Translational Control during Regeneration of Skeletal Muscle Fibers J. Biol. Chem., September 23, 2005; 280(38): 32997 - 33005. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. V. Chakkalakal, M.-A. Harrison, S. Carbonetto, E. Chin, R. N. Michel, and B. J. Jasmin Stimulation of calcineurin signaling attenuates the dystrophic pathology in mdx mice Hum. Mol. Genet., February 15, 2004; 13(4): 379 - 388. [Abstract] [Full Text] [PDF] |
||||
![]() |
F. Haddad, R. R. Roy, H. Zhong, V. R. Edgerton, and K. M. Baldwin Atrophy responses to muscle inactivity. II. Molecular markers of protein deficits J Appl Physiol, August 1, 2003; 95(2): 791 - 802. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. A. Huey, F. Haddad, A. X. Qin, and K. M. Baldwin Transcriptional regulation of the type I myosin heavy chain gene in denervated rat soleus Am J Physiol Cell Physiol, March 1, 2003; 284(3): C738 - C748. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. J. Blake, A. Weir, S. E. Newey, and K. E. Davies Function and Genetics of Dystrophin and Dystrophin-Related Proteins in Muscle Physiol Rev, April 1, 2002; 82(2): 291 - 329. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. O. Gramolini, G. Belanger, and B. J. Jasmin Distinct regions in the 3' untranslated region are responsible for targeting and stabilizing utrophin transcripts in skeletal muscle cells J. Cell Biol., September 17, 2001; 154(6): 1173 - 1184. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |