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© The Rockefeller University Press,
0021-9525/1998//1167 $5.00
The Journal of Cell Biology, Volume 140, Number 5,
, 1998 1167-1176
Article |
Antagonistic Roles of Neurofilament Subunits NF-H and NF-M Against NF-L in Shaping Dendritic Arborization in Spinal Motor Neurons
Dendrites play important roles in neuronal function. However, the cellular mechanism for the growth and maintenance of dendritic arborization is unclear. Neurofilaments (NFs), a major component of the neuronal cytoskeleton, are composed of three polypeptide subunits, NF-H, NF-M, and NF-L, and are abundant in large dendritic trees. By overexpressing each of the three NF subunits in transgenic mice, we altered subunit composition and found that increasing NF-H and/or NF-M inhibited dendritic arborization, whereas increasing NF-L alleviated this inhibition. Examination of cytoskeletal organization revealed that increasing NF-H and/or NF-M caused NF aggregation and dissociation of the NF network from the microtubule (MT) network. Increasing NF-H or NF-H together with NF-M further reduced NFs from dendrites. However, these changes were reversed by elevating the level of NF-L with either NF-H or NF-M. Thus, NF-L antagonizes NF-H and NF-M in organizing the NF network and maintaining a lower ratio of NF-H and NF-M to NF-L is critical for the growth of complex dendritic trees in motor neurons.
Abbreviations used in this paper: MAP, microtubule-associated protein; MT, microtubule; NF, neurofilaments.
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