Cleanup After a Breakup

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Science  03 Apr 2009:
Vol. 324, Issue 5923, pp. 15
DOI: 10.1126/science.324.5923.15c

When nerves are damaged, the parts of the axon fibers that are distal to the point of damage become disconnected from the neuronal cell body whence regulatory and metabolic support comes. The distal axonal segment usually degenerates in a characteristic manner termed Wallerian degeneration. The signals that bring about the orderly disintegration and cleanup of axonal debris are the subject of a study by Miller et al. When the axons of Drosophila olfactory neurons were broken by removal of the antennae, the remaining axon segments disintegrated in wild-type flies; however, in flies in which the protein kinase DLK had been deleted, disintegration proceeded much more slowly. Similarly, in mice, the disintegration of damaged axons in dorsal root ganglia cultures and in sciatic nerves in vivo was slowed in the absence of DLK. The downstream kinase JNK, through which DLK acts, functions in the disconnected axon segment early after the damage occurs. — PJH

Nat. Neurosci. 12, 10.1038/nn.2290 (2009).

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