Cell connections help keep the brain’s daily clock stable despite mutations

Per1 and Cry1 are essential for sustained rhythms in peripheral tissues and neurons, while Per2 is also necessary.

• Bioluminescence imaging was used to monitor Per2 gene expression in clock mutant mice.
• Deficiencies in Per2, Per1, and Cry1 are associated with disruptions in sustained circadian rhythmicity.
• Cry2 and Per3 deficiencies primarily lead to defects in the period length of rhythms.
• Oscillator interactions in the suprachiasmatic nuclei can compensate for the loss of Per1 or Cry1, maintaining rhythmicity in mutant SCN slices.
• Behavioral rhythms do not always accurately reflect the underlying cellular clock functions.

Simplified