![]() ( G– H′′) In the glia − group, v'ada axons also failed to regenerate (arrow). ( E– F′′) In the glia + group, v'ada axons were also able to extend beyond the lesion site (circle) and regenerate along glia processes (arrowheads). ( E–H) Axon regeneration of class IV da neuron v'ada. ( A′– L′) Schematic drawings of the neurons in A–L, depicting only the cell body and axon. ( C– D′′) In the glia − group, where both axon and glia processes were severed (circle), ddaC axons failed to show regeneration (arrow). ( A– B′′) In the glia + group, where only axons were severed (circle) without obvious damage to the wrapping glia processes, ddaC axons regrew beyond the lesion site, following a trajectory demarcated by glia processes (arrowheads). ( A–D) Axon regeneration of class IV da neuron ddaC ( ppk-CD4-tdGFP/+ repo-Gal4, UAS-mRFP/+). We thus established an important new model system-the fly da neuron regeneration model that resembles the mammalian injury model-with which to study and gain novel insights into the regeneration machinery.ĭa neuron axon regeneration in the periphery displays class specificity and glia dependence. Our study begins to reveal mechanisms for dendrite regeneration, which depends on both extrinsic and intrinsic factors, including the PTEN-Akt pathway that is also important for axon regeneration. Dendrite regeneration is restrained via inhibition of the Akt pathway in da neurons by the epithelial cell-derived microRNA bantam but is facilitated by cell-autonomous activation of the Akt pathway. Moreover, those da neurons capable of axon regeneration also display dendrite regeneration, which is cell type-specific, developmentally regulated, and associated with microtubule polarity reversal. Here we report that, like the axons of mammalian sensory neurons, the axons of certain Drosophila dendritic arborization (da) neurons are capable of substantial regeneration in the periphery but not in the CNS, and activating the Akt pathway enhances axon regeneration in the CNS. Whether dendrites also regenerate is unknown. Both cell-intrinsic and extrinsic pathways govern axon regeneration, but only a limited number of factors have been identified and it is not clear to what extent axon regeneration is evolutionarily conserved.
0 Comments
Leave a Reply. |