Fig. 8: TRF normalizes gene circadian rhythms in liver, mammary fat, and breast tumors.

a QPCR analysis of the core clock genes in liver, MFP, and tumor samples from mice on normal chow collected at different times (ZT0, 4, 8, 12, 16, 20) over a 24 h period. ZT0 indicates 6 am and the start of the light phase. Data is plotted over 48 h to facilitate visualization of the circadian rhythms. Gray rectangles indicate period of lights off. b QPCR analysis of the clock genes Bmal1, Per1, and Cry1 in liver samples collected at different times over 24 h in mice on ad libitum HFD (AL—orange), time-restricted HFD (TRF—green) or chow diet (NC—blue). Data are presented as mean normalized expression ± SEM (n = 4 mice/time/group). c QPCR analysis of the clock genes Bmal1, Per1, and Cry1 in MFP samples over 24 h in mice on ad libitum HFD or TRF or normal chow diet (n = 4 mice/time/group), colors as in b. d QPCR analysis of the clock genes Bmal1, Per1, and Cry1 in tumor samples collected over 24 h (n = 4 mice/time/group), colors as in b. Data in b, c, and d are plotted over 48 h to facilitate visualization of the circadian rhythms. e QPCR analysis of the clock genes Bmal1, Per1, and Cry1 in Py230 cells following a 50% serum shock without (HS–blue) or with 10 nM insulin (HS + ins–red) collected at different times over 48 h (n = 3/time/group). Dotted line indicates a common shared curve that explains the variation in the data. Data are presented as mean normalized expression (n = 4/time/group), error bars are omitted for clarity. Twenty-four hour rhythms were analyzed statistically using RAIN with a period of 24 ± 4 h, and circadian curves fitted using PRISM using the equation Y = baseline + amplitude*cos(frequency*X + phaseshift) using a frequency of 0.2618 for a 24 h period. Genes with statistically significant circadian rhythms are shown as curves, acyclic genes are shown as horizontal lines. Statistical data and circadian parameters are given in Supplementary Table 1.