 |
||||
|
||||
|
||||
|
||||
Previous Article | Next Article
The Journal of Neuroscience, May 1, 1998, 18(9):3297-3313
Selective Fasciculation and Divergent Pathfinding Decisions of Embryonic Chick Motor Axons Projecting to Fast and Slow Muscle Regions
Louise D. Milner, Victor F. Rafuse, and Lynn T. Landmesser Department of Neurosciences, Case Western Reserve University, Cleveland, Ohio 44106-4975
Proper motor function requires the precise matching of motoneuron and muscle fiber properties. The lack of distinguishing markers for early motoneurons has made it difficult to determine whether this matching is established by selective innervation during development or later via motoneuron-muscle fiber interactions. To examine whether chick motoneurons selectively innervate regions of their target containing either fast or slow muscle fibers, we backlabeled neurons from each of these regions with lipophilic dyes. We found that motor axons projecting to fast and slow muscle regions sorted into separate but adjacent fascicles proximally in the limb, long before they reached the muscle. More distally, these fascicles made divergent pathfinding decisions to course directly to the appropriate muscle fiber region. In contrast, axons projecting to different areas of an all-fast muscle did not fasciculate separately and became more intermingled as they coursed through the limb. Selective fasciculation of fast- and slow-projecting motoneurons was similar both before and after motoneuron cell death, suggesting that motoneurons specifically recognized and fasciculated with axons growing to muscle regions containing the appropriate muscle fiber type. Taken together, these results strongly support the hypothesis that "fast" and "slow" motoneurons are molecularly distinct before target innervation and that they use these differences to selectively fasciculate, pathfind to, and branch within the correct muscle fiber region from the outset of neuromuscular development.
Key words: selective fasciculation; selective innervation; motoneuron; muscle; specificity; axon pathfinding; guidance; neuromuscular development; fast-slow innervation
Copyright © 1998 Society for Neuroscience 0270-6474/98/1893297-17$05.00/0
This article has been cited by other articles:
Z. A. Rana, K. Gundersen, and A. Buonanno
Activity-dependent repression of muscle genes by NFAT
PNAS, April 15, 2008; 105(15): 5921 - 5926.
[Abstract] [Full Text] [PDF]
L. Stepanek, A. W. Stoker, E. Stoeckli, and J. L. Bixby
Receptor Tyrosine Phosphatases Guide Vertebrate Motor Axons during Development
J. Neurosci., April 13, 2005; 25(15): 3813 - 3823.
[Abstract] [Full Text] [PDF]
C. K. Franz, U. Rutishauser, and V. F. Rafuse
Polysialylated Neural Cell Adhesion Molecule Is Necessary for Selective Targeting of Regenerating Motor Neurons
J. Neurosci., February 23, 2005; 25(8): 2081 - 2091.
[Abstract] [Full Text] [PDF]
H.-H. Chen, J. W. Yip, A. F. R. Stewart, and E. Frank
Differential expression of a transcription regulatory factor, the LIM domain only 4 protein Lmo4, in muscle sensory neurons
Development, January 11, 2002; 129(21): 4879 - 4889.
[Abstract] [Full Text] [PDF]
M. F. Usiak and L. T. Landmesser
Neuromuscular Activity Blockade Induced by Muscimol and d-Tubocurarine Differentially Affects the Survival of Embryonic Chick Motoneurons
J. Neurosci., September 15, 1999; 19(18): 7925 - 7939.
[Abstract] [Full Text] [PDF]
|
|
|
|
 |
|