Different roles of three clock genes in the brain's daily rhythm control center

Mice with disrupted mPer1 or mPer2 genes exhibited severely disrupted locomotor activity rhythms during constant darkness.

• Disruption of mPer1 or mPer2 genes led to significant alterations in locomotor activity patterns.
• mPer2 mutant mice showed blunted clock gene RNA rhythms in the suprachiasmatic nucleus, unlike mPer1-deficient mice.
• Both mPer1 and mPer2 mutations resulted in reduced peak levels of mPER and mCRY1 proteins.
• Behavioral rhythms of mPer1/mPer3 and mPer2/mPer3 double mutants were similar to those of single mutants, indicating mPer3's role is separate from the core clock.
• mPer1/mPer2 double-mutant mice displayed immediate arrhythmic behavior, suggesting a critical interaction between mPER1 and mPER2 in maintaining rhythmicity.

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