Daily rhythms in gene regulators and tissue-specific DNA packaging explain 24-hour gene activity in different organs

Two distinct regulatory modes underlie tissue-specific rhythms in mouse physiology.

• Tissue-specific oscillations in transcription factor activity are linked to feeding-fasting cycles in the liver and sodium homeostasis in the kidney.
• Clock and tissue-specific transcription factors colocalize at distal enhancers, influencing gene expression.
• Chromosome conformation capture identified liver-specific chromatin loops that connect clock-bound enhancers to liver-specific promoters.
• This chromatin looping is promoter-specific and occurs within a distance of less than 10 kilobases.
• Enhancers can selectively contact rhythmic promoters while excluding nearby nonrhythmic alternatives, highlighting spatial regulation of gene expression.

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