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Role of long‐range repulsive forces in organizing axonal neurofilament distributions: Evidence from mice deficient in myelin‐associated glycoprotein
Author(s) -
Kumar Sanjay,
Yin Xinghua,
Trapp Bruce D.,
Paulaitis Michael E.,
Hoh Jan H.
Publication year - 2002
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/jnr.10249
Subject(s) - neurofilament , axon , myelin , monte carlo method , physics , biophysics , myelin basic protein , glycoprotein , neuroscience , myelin associated glycoprotein , range (aeronautics) , biology , chemistry , materials science , mathematics , central nervous system , statistics , immunohistochemistry , microbiology and biotechnology , immunology , composite material
When the axon of a motor neuron is sectioned and visualized by electron microscopy, a two‐dimensional distribution of neurofilaments (NFs) with nonrandom spacing is revealed; this ordered arrangement implies the presence of physical interactions between the NFs. To gain insight into the molecular basis of this organization, we characterized NF distributions from mouse sciatic nerve cross sections using two statistical mechanical measures: radial distribution functions and occupancy probability distributions. Our analysis shows that NF organization may be described in terms of effective pairwise interactions. In addition, we show that these statistical mechanical measures can detect differences in NF architecture between wild‐type and myelin‐associated glycoprotein null mutant mice. These differences are age dependent, with marked contrast between the NF distributions by 9 months of age. Finally, using Monte Carlo simulations, we compare the experimental results with predictions for models in which adjacent NFs interact through rigid cross bridges, deformable cross bridges, and long‐range repulsive forces. Among the models tested, a model in which the filaments interact through a long‐range repulsive force is most consistent with the results of our analysis. © 2002 Wiley‐Liss, Inc.