FIGURE 1.

Daily rhythms of Srebp-1 mRNA (A) and protein (B) levels, differential Srebp-1a and Srebp-1c mRNA levels (C), and mRNA levels of clock-related genes Dbp (D) and Rev-erbα (E) in the mouse liver. Male wild-type C57BL/6 mice were housed in a 12-h light/12-h dark cycle (12:12LD, light/dark periods are represented by open/solid boxes) with feeding ad libitum for at least 2 weeks. Livers were excised at 4-h intervals from 3 mice at each time point and subjected to preparation of total RNA and whole tissue extracts. A, D, and E, Northern blot analysis of total RNA for detection of mRNAs of Srebp-1, Dbp (reproduced partly from Ref. 6), and Rev-erbα, respectively. A chemiluminogram for detection of each mRNA is shown along with ethidium bromide staining for 28 S and 18 S rRNAs. Below, quantified results for each mRNA level are presented. B, Western blot analysis of liver extracts. Chemiluminograms for detection of SREBP-1 and GAPDH are shown. Below, quantified results for SREBP-1 levels (normalized to GAPDH levels) are represented. C, quantitative reverse transcription PCR analysis. Srebp-1a and Srebp-1c mRNA levels were differentially measured using forward primers each specific to alternative first exons as described under “Experimental Procedures.” All quantified mRNA or protein levels relative to the maximum value (100%) are represented as mean ± S.E. p values for rhythmicity were assessed by 1-way ANOVA test.