First Author | Zhu Q | Year | 1998 |
Journal | J Cell Biol | Volume | 143 |
Issue | 1 | Pages | 183-93 |
PubMed ID | 9763430 | Mgi Jnum | J:55453 |
Mgi Id | MGI:1343581 | Doi | 10.1083/jcb.143.1.183 |
Citation | Zhu Q, et al. (1998) Disruption of the NF-H gene increases axonal microtubule content and velocity of neurofilament transport: relief of axonopathy resulting from the toxin beta,beta'-iminodipropionitrile [see comments]. J Cell Biol 143(1):183-93 |
abstractText | To investigate the role of the neurofilament heavy (NF-H) subunit in neuronal function, we generated mice bearing a targeted disruption of the gene coding for the NF-H subunit. Surprisingly, the lack of NF-H subunits had little effect on axonal calibers and electron microscopy revealed no significant changes in the number and packing density of neurofilaments made up of only the neurofilament light (NF-L) and neurofilament medium (NF-M) subunits. However, our analysis of NF-H knockout mice revealed an approximately 2.4-fold increase of microtubule density in their large ventral root axons. This finding was further corroborated by a corresponding increase in the ratio of assembled tubulin to NF-L protein in insoluble cytoskeletal preparations from the sciatic nerve. Axonal transport studies carried out by the injection of [35S]methionine into spinal cord revealed an increased transport velocity of newly synthesized NF-L and NF-M proteins in motor axons of NF-H knockout mice. When treated with beta,beta'-iminodipropionitrile (IDPN), a neurotoxin that segregates microtubules and retards neurofilament transport, mice heterozygous or homozygous for the NF-H null mutation did not develop neurofilamentous swellings in motor neurons, unlike normal mouse littermates. These results indicate that the NF-H subunit is a key mediator of IDPN-induced axonopathy. |