Differential Expression of the Circadian Clock in Maternal and Embryonic Tissues of Mice
Figure 2
Twenty-four-hour expression profiles of Per2 and Bmal1 mRNA in whole embryos and maternal liver during embryogenesis.
Whole embryos were collected every 4 hours for 24 hours on E10-E11 (A), E14-E15 (B) and E18-E19 (C) and mRNA was measured using quantitative real-time RT-PCR. The 0 and 24 hour time points were repeated, independent measures of the same time of day. Maternal livers demonstrated robust variation in both Per2 and Bmal1 at all ages (P<0.0001), consistent with the rhythms expected for these genes. The mRNA of whole embryos failed to show a clear rhythm in either Per2 or Bmal1 at E10-E11 and E18-E19. Low but statistically significant fluctuations were observed for Per2 and Bmal1 at E14-E15 (p<0.01). RNA levels were normalized to the control gene, gapdh. Symbols represent the mean ± standard error of the mean (SEM) of three biological replicates. The maximum maternal liver RNA for each stage of gestation was set to 100 and the rest of maternal and embryonic samples are presented relative to that maximum.