FIGURE 5.

Per2 knockout alters the rhythmic mRNA expression of clock-controlled genes in the adult zebrafish heart. qRT-PCR analysis of expression levels of four putative CCGs (A) timp3, (B) mef2a, (C) cox6a2, and (D) smad3a in WT and per2 KO heart tissues. Sets (n = 3) of 4 WT and per2 KO fish (each set containing two males and two females) were maintained under LD cycle (14 h light-10 h dark) conditions, hearts were dissected and pooled for RNA extraction at 6-h intervals during a sampling window of 24 h. Mean mRNA relative expression ± SD is plotted on the y-axis; zeitgeber time (ZT) is plotted on the x-axis. Zeitgeber times are indicated for each sample. ZT0 corresponds to lights-on, ZT14 to lights-off. A change in rhythm was observed for timp3, cox6a2, mef2a, and smad3a, as determined by a significant ANOVA Genotype × Time interaction effect for all genes (p < 0.01, see Table 1). Asterisks represent levels of significance in comparing the two genotypes at each time point individually, corrected by Sidak’s method (***p < 0.001, *p < 0.05).