TNFa/TNFR2 signaling is required for glial ensheathment at the dorsal root entry zone
Fig 6
TNFR2 is required for glial ensheathment of DRG axons at the DREZ.
(A) Images of Tg(sox10:eos) wildtype, tnfr2 morphant and tnfr2 F0 CRISPR mutant larvae at 72 hpf showing a central branch that is ensheathed by sox10+ glia (arrow) in wildtype but not tnfr2 morphants or tnfr2 F0 CRISPR mutants (arrow). (B) Quantification of data from panel A (wt n = 40 DRG, tnfr2 MO n = 31 DRG, tnfr1 = 24 DRG). (C) Images of spinal column tissue from wildtype and TNFR2-/- P0 mouse embryos labeled with antibodies to S100 (green) and βIII Tubulin (red). Traced area denotes central projection that extends into the spinal cord. (D) Electron microscopy images of DRG tissue from wildtype and TNFR2-/- pups showed a reduction in the ensheathment of axonal bundles. (E,F) Quantification of ensheathed vs unensheathed bundles in wildtype and TNFR2-/- pups (3 animals, wt n = 108 nerve bundles, TNFR2-/- n = 68 nerve bundles). (G,H) Quantification of the number of axons per small-caliber bundle in wildtype and TNFR2-/- pups. (I) Images from a 24-hour time-lapse movie of a Tg(sox10:eos) embryo injected with tnfr2 MO. Fisher’s exact test (B,F,H). Students t-test (E,F). Scale bars, 25 μm (A,C,I), 5 μm (D).