| Research Abstract |
The clock gene of Drosophila containing a hexamer repeat sequence(ACAGGC)_n (period, per, repeat)is reported to be concerned in ther circadian rhythm. Young and his co-workers(1987)succeeded to clone a mouse genomic DNA containing the per repeat(cp2.2). In this study, temporal and spacial expression of CP2.2F and RB15 was examined in the adult rat brain by in situ hybridization. The former is a family of genes detected by using cp2.2 as a probe, and the latter is a gene corresponding to pRB15, one of the 11 cDNA recombinants homologous to cp2.2 from the rat brain cDNA libraly. Both genes were expressed in almost all neurons. However, it was in the suprachiasmatic nucleus that fluctuation to the genes under the light-dark cycle was apparently observed ; an intensive hybridization signal in the middle of the day and a weak in the middle of the night(p<0.01). On the other hand, the signal stayed relatively constant in other brain regions. A weak expression of both genes(CP2.2F and RB15)was detected in some glial and ependymal cells in the day but only a few in the night.
The present findings suggest that CP2.2F and RB15 may contribute to the circadian rhythm in the rat nervous system.
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