Fig. S8

Wnt/β-catenin signaling selectively controls col12a1a/b transcription in a spinal lesion site during the initial phase of axon regeneration.

(a) List of genes encoding collagen-chains that were not detectably expressed in the lesion site of untreated or Wnt/β-catenin pathway-inhibited (IWR-1) animals at 1 dpl by in situ hybridization.

(b) In situ hybridization (ISH) on section confirms that col12a1a expression is confined to the lesion site.

(c) RT-PCR of trunk tissue surrounding the lesion site confirms that lesion-induced upregulation of col12a1a/b expression depends on Wnt/β-catenin signaling.

(d) Inhibition of Wnt/β-catenin signaling (IWR-1) between 1-2 dpl does not affect expression of col12a1a/b in the lesion site, as determined by quantification of fluorescence in situ hybridization signal (t-test: n.s. indicates not significant).

(e) Expression of axin2, a direct Wnt/β-catenin target, but not of col12a1a or col12a1b is strongly reduced in the lesion site within 6 hours of pathway inhibition by heat shock induced overexpression of axin1 in hs:Axin1 transgenic animals. This suggests indirect transcriptional control of col12a1a/b genes by the Wnt/β-catenin pathway.

(f) pdgfrb:GFP-expressing cells accumulate in the lesion site after lesion.

(g) The majority of col12a1a/b-expressing cells (red) co-express gfp mRNA (green) in lesioned pdgfrb:GFP transgenic animals (arrow), a marker for pericytes and reactive fibroblasts.

(h) Interference with Wnt/β-catenin signaling (IWR-1) does not overtly inhibit appearance of pdgfrb:GFP⁺ cells.

(a-h) Views are lateral (d-f, h; dorsal is up, rostral is left) or transversal (b, g; dorsal is up). BF: brightfield. Scale bars: whole mounts, 100 μm; sections, 100 μm. Error bars indicate s.e.m.