Investigation on the biological limit cycles by using transgenic mice.

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Two-clock system in the SCN and cause of jet lagWe found the restriction of Per1 gene induction to the ventrolateral region of the SCN.After brief light exposure in the night, rats showed high level of Per1 mRNA induction in the ventrolateral region of the suprachiasmatic nucleus (SCN). The results suggested that there are two types of clocks in the SCN ; light responsive and light unresponsive. To show the two-oscillator system in the SCN clearly, we utilized a large rapid light-dark cycle shift. After the 10 hours delay of LD cycle, we found the dissociation of the internal timing system in the SCN ; the Per1 expression in the ventrolateral region showed a rapid large shift while the dorsomedial regions were far less affected. The following resynchronization process of the two regions was rather slow, requiring several days. These findings suggest that there are potential two clocks in the SCN, which could be dissociated by a certain perturbation. These findings also suggest that jet … More lag is caused by delayed shift of the clocks in the dorsomedial region of the SCN.Investigation on the transgenic flies carrying mouse Per genesWe investigated the functional conservation of per by introducing the mouse mPer1 and mPer2 genes, driven by the Drosophila timeless (tim) promoter, into Drosophila melanogaster. Behavioral assays showed that both mPer constructs restored rhythms in per^<01>flies that are otherwise arrhythmic due to a lack of endogenous per protein (PER). This study demonstrates that both mPer1 and mPer2 can function as clock components, and has implications for functional analysis of the different per genes.Analysis on the transgenic mouse carrying mPer1 genesWe obtained the cDNAs containing coding region and promoter regions of mPer1, Per2, and Per3. These cDNAs corresponding regions of Per1, Per2 and Per3 tagged with FLAG are subcloned into expression vectors. We transfected these expression vectors into cell lines and obtained enough expression of these proteins. Now we are trying to establish the transgenic mice carrying these Per genes. Less