Expression of period repeat sequence consisting in Drosopila clock gene in the rat brain : Insitu hybridization study.

据报道，果蝇含有六聚体重复序列（ACAGGC）_n （period, per, repeat）的时钟基因与果蝇的昼夜节律有关。Young和他的同事（1987）成功克隆了一个含有每重复序列（cp2.2）的小鼠基因组DNA。本研究采用原位杂交技术检测了CP2.2F和RB15在成年大鼠脑中的时空表达。前者是一个以cp2.2为探针检测到的基因家族，后者是大鼠脑cDNA文库中与cp2.2同源的11个cDNA重组体之一pRB15对应的基因。这两种基因在几乎所有神经元中都有表达。然而，在视交叉上核中，基因在明暗循环下明显波动；白天杂交信号强，夜间杂交信号弱（p<0.01）。另一方面，信号在大脑的其他区域保持相对恒定。CP2.2F和RB15这两个基因在白天在一些胶质细胞和室管膜细胞中检测到弱表达，但在夜间只有少数表达。本研究结果提示CP2.2F和RB15可能参与大鼠神经系统的昼夜节律。

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.