Proteomics analysis of regulation by Bmal1 and physiological time-restricted feeding

To define regulation of tissue proteomes by Bmal1, daily feeding rhythm, and the interaction, we employed Bmal1-stopFL mice, which do not express the main transcriptional activator of the molecular clock, Bmal1, except in cre recombinase-expressing cells1,2 (Figure 1A). Bmal1-stopFL mice lacking cre (Bmal1 knockout, KO) are analogous to Bmal1-null mice and display severely impaired behavioral and molecular rhythms1-3. Hepatocyte-specific Alfp-cre and skeletal muscle-specific Hsa-cre genes were introduced to generate a single line wherein both hepatocyte and skeletal muscle Bmal1 were reconstituted (Liver+Muscle-RE), i.e., rescued (Smith, Koronowski et al. 2023). This approach had the benefit of analyzing liver and muscle from the same mice but comes with the qualification that the abundance of some proteins may be influenced by Bmal1 function in the other tissue, or by a synergistic effect of Bmal1 in both tissues, rather than through rescue of local Bmal1 function alone. Proteomic anlaysis was performed in liver and skeletal muscle.