Astrocytes phagocytose focal dystrophies from shortening myelin segments in the optic nerve of Xenopus laevis at metamorphosis.

摘要: Oligodendrocytes can adapt to increases in axon diameter through the addition of membrane wraps myelin segments. Here, we report that segments also decrease their length response optic nerve (ON) shortening during Xenopus laevis metamorphic remodeling. EM-based analyses revealed segment is accomplished by focal myelin-axon detachments and protrusions from otherwise intact Astrocyte processes remove these dystrophies using known phagocytic machinery, including opsonin milk fat globule-EGF factor 8 (Mfge8) downstream effector ras-related C3 botulinum toxin substrate 1 (Rac1). By end shortening, one-quarter all ON enwrapped or internalized astrocytes. As opposed removal degenerating macrophages, which usually associated with axonal pathologies, astrocytes selectively large amounts without damaging axons this developmental remodeling event.