Circadian rhythms in the absence of the clock gene Bmal1

In knockout mice, both skin fibroblasts and liver slices exhibited 24-hour oscillations of the transcriptome, proteome, and phosphoproteome over 2 to 3 days without external cues.

• Deletion of the transcription factor BMAL1 abolishes typical 24-hour activity patterns, a known measure of circadian clock output.
• Despite the absence of BMAL1, tissues demonstrated sustained molecular rhythms, indicating the presence of an alternative internal pacemaker.
• These oscillations occurred without external drivers, such as light or temperature changes, suggesting intrinsic regulatory mechanisms are at play.
• Potential underlying mechanisms may include transcriptional regulation through ETS family transcription factors and non-transcriptional processes involving redox changes.

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