Figure 1.

Comparison of the candidate gene expressions in the acute phase between Xenopus laevis tadpoles and aged mice after spinal cord injury

(A) The nonclustering heatmap shows the differential expression of basic-helix-loop-helix (bHLH) transcription factors during the regenerative (R) and nonregenerative (NR) stages in the spinal cord after injury in Xenopus laevis (X. laevis).

(B) Quantification of mRNA expression levels for candidate genes (Neurod4, Neurod1, Atoh1, Neurog2, Ascl1) in the mouse SCI model. Gene expression levels were compared to those of the Sham (n = 3 mice per group). Statistical analysis was performed using student's t-test: ∗p < 0.05, ∗∗p < 0.005, ∗∗∗p < 0.001 and N.S. = not significant. P = 0.1770 to 1 DPI, 0.7074 to 3 DPI in Neurod4; P = 0.0225 to 1 DPI, 0.2071 to 3 DPI in Neurod1; P = 0.0022 to 1 DPI, 0.0328 to 3 DPI in Atoh1; P = 0.0073 to 1 DPI, 0.0329 to 3 DPI in Neurog2; P < 0.0001 to 1 DPI, 0.1935 to 3 DPI in Ascl1. Data represent the mean ± S.D.

(C) Superior expression of genes of X. laevis tadpole (in both L and S chromosomes) to aged mice in the stage for nerve regeneration. The bars indicate that the sum of FPKM ratios in the injured group over the sham group in X. laevis after SCI at 1 and 2 DPIs in the R stage (R1 +R2) was divided by the sum of qPCR values in the SCI group over the sham group at 1 and 3 DPIs (1 DPI +3 DPI). FPKM, fragments per kilobase of transcript per million. DPI, days post injury.

See also Table S1.