Fig. 4.

GRK-2 protein and mRNA levels in constant conditions in C. elegans. (A) A representative immunoblot probed for GRK-2. After entrainment to a temperature cycle, the levels of GRK-2 protein show a circadian rhythm in free-running conditions (13 °C, darkness). The x axes are labeled as described for Fig. 1B. For each time series, the data were quantified by densitometry and normalized to the highest value. The mean ± SEM of four biological replicates is shown. To test for rhythmicity of the time series, a sinusoidal curve was fitted to the data using Circwave (P < 0.01). Statistic analysis with Circwave and JTK-Cycle is shown in Table S1. (B) grk-2 mRNA levels are not rhythmic under the same protocol used for protein quantification. The expression of grk-2 was measured by quantitative RT-PCR. The results were normalized to the amount of act-4 mRNA and then to the sample with the highest expression level. The x axes are labeled as described in Fig. 1B. The plot shows the mean ± SEM of three biological replicates.