Clock gene expressions in the suprachiasmatic nucleus and other areas of the brain during rhythm splitting in CS mice.
The CS mouse is a mutant strain which displays spontaneous splitting in the circadian locomotor rhythm under continuous darkness. To clarify whether the rhythm splitting occurs in the suprachiasmatic nucleus (SCN) where the mammalian circadian clock is located, the circadian rhythmicities of mammalian clock genes, mPer1, mBMAL1 and mClock, were examined in the SCN and cerebral cortex during rhythm splitting. The circadian profiles of the clock genes during rhythm splitting were essentially the same as those observed under unsplit conditions. However, the mPer1 gene expression throughout the day was bimodal in the piriform and cingulate cortices, peaking in correspondence with two split components of behavioral rhythm. These results indicate that the circadian profiles of three clock gene expressions in the SCN are not consistent with the overt circadian locomotor rhythm, suggesting that the site of rhythm splitting is somewhere outside the SCN, or alternatively different subregions or other clock genes in the SCN are involved in rhythm splitting.
Department of Physiology, Division of Physiological Science, Hokkaido University Graduate School of Medicine, 060-8638, Sapporo, Japan. hiroabe@med.hokudai.ac.jp
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D056930:ARNTL Transcription Factors; D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins; D001522:Behavior, Animal; D001923:Brain Chemistry / Q000502:physiology; D056926:CLOCK Proteins; D018797:Cell Cycle Proteins; D002940:Circadian Rhythm / Q000502:physiology*; D015870:Gene Expression / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D009687:Nuclear Proteins / Q000235:genetics; D056950:Period Circadian Proteins; D012333:RNA, Messenger / Q000032:analysis; D013493:Suprachiasmatic Nucleus / Q000502:physiology*; D015534:Trans-Activators / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics
D056930:ARNTL Transcription Factors; D051792:Basic Helix-Loop-Helix Proteins; D056926:CLOCK Proteins; D018797:Cell Cycle Proteins; D009687:Nuclear Proteins; D056950:Period Circadian Proteins; D012333:RNA, Messenger; D015534:Trans-Activators; D014157:Transcription Factors; C538961:Bmal1 protein, mouse; C539023:Per1 protein, mouse; C538944:Clock protein, mouse