Figure 2.

Enzymes critical to PGE₂ production are upregulated in regenerating adult hearts. (A) qPCR studies demonstrated that cox1 levels in uninjured zebrafish ventricles were significantly higher than either cox2a or cox2b transcripts. Gene expression was calculated relative to cox2a (mean ± s.e.m. n = 4–5 biological replicates; 3–5 pooled ventricles per replicate. One-way ANOVA followed by Tukey’s multiple comparisons test. *P < 0.05, **P < 0.01, ***P < 0.001). (B) At 3 dpa, cox2a is the only Cox isozyme significantly upregulated relative to uninjured hearts, as determined by qPCR. (mean ± s.e.m. n = 4–5 biological replicates; 3–5 pooled ventricles per replicate. Student’s t-test. **P < 0.01). (C) Relative to uninjured hearts, ptges is significantly upregulated at 3 dpa. (mean ± s.e.m. n = 4 biological replicates; 3–5 pooled ventricles per replicate. Student’s t-test. *P < 0.05). (D,E) Representative images of cox2a (D) and cox2b (E) expression domains as revealed by in situ hybridization studies. (n = 4 biological replicates; brackets = approximate amputation zone; arrowheads demarcate signal within the injury zone). Representative (−) control 2 dpa hearts were hybridized with cox2a riboprobe without anti-DIG antibody (top right panel) or with anti-DIG only (bottom right panel). (n = 2 biological replicates).