A new daily rhythm gene mainly active in the brain’s internal clock center

A robust circadian rhythmic expression of the newly identified mPer2 gene is predominantly observed in the suprachiasmatic nuclei (SCN) of mice.

• mPer2 shares a similar amino acid sequence with mPer1 and Drosophila Period, suggesting it is part of the same gene family.
• Peak expression of mPer2 transcripts occurs 8 hours later in light-dark conditions and 4 hours later in dark-dark conditions compared to mPer1.
• A brief light exposure during the early subjective night causes a delayed increase in mPer2 transcripts, in contrast to the quicker response of mPer1.
• mPer2 is co-expressed with mPer1 in individual SCN cells, indicating a potential interaction between these clock genes.
• Mammalian period genes exhibit molecular diversity, which may contribute to the establishment of stable circadian rhythms.

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