Figure 1. A posterior glycolytic gradient in the mouse tail bud.
(A) Lateral view of the posterior region of E 9.5 day mouse embryo showing the 3 domains used for metabolomics analysis. TB: Tail bud, S: somite, A-PSM and P-PSM: Anterior and Posterior Presomitic Mesoderm respectively. Each domain contains approximately 5000 cells. Scale bar :100 μm.
(B) Clustering analysis of the 39 metabolites showing the most significant differential expression along the posterior region of the embryo. Color bar shows fold change from mean. Red box highlights metabolites downregulated and blue box metabolites upregulated during differentiation.
(C) Schematic representation of the mouse glycolytic cascade. Red labeling indicates metabolites detected in the metabolomics analysis. Yellow labeling indicates the glycolytic enzymes transcripts downregulated in the mouse embryo tail bud and PSMs.
(D) Expression profiles of the metabolites associated to glycolysis detected in the metabolomics analysis (* Significant at p<0.05 with t-test). The color bar shows fold change from mean of all triplicate samples.
(E–G) Enzymatic detection of relative lactate levels, Cytochrome C oxidase activity, and relative ATP concentrations during tail bud differentiation. Graphs show triplicate experiments. Values were normalized by P-PSM, Error bars are ±SD. Statistical significance was assessed with one way ANOVA followed by Tukey’s test, * p<0.05, ** p<0.01. (H) Expression profiles of transcripts coding for glycolytic enzymes downregulated in the mouse PSM during differentiation. Each value is normalized to the mean of MAS values of all triplicate mouse microarray series. The color bar shows fold change from mean.
(I) Lateral view of the tail bud region of 9.5-day mouse embryo stained with an antibody against Glut3 (n=5). Maximum projection of confocal sections. Fluorescence intensity is shown by pseudo-color image (16 color) using image J. Higher levels of Glut3 proteins are indicated in red-yellow. Scale bar : 100 μm.