Mouse dexamethasone-induced RAS protein 1 gene is expressed in a circadian rhythmic manner in the suprachiasmatic nucleus.
We identified the Dexamethasone-induced RAS protein 1 (Dexras1) gene as a cycling gene in the suprachiasmatic nucleus (SCN). Investigation of the whole brain using in situ hybridization demonstrated the localization of the expression of the gene in the SCN, thalamus, piriform cortex and hippocampus. However, rhythmic expression of the gene was observed only in the SCN. The rhythmic change in gene expression during 1 day was approximately five-fold, and the maximum expression was observed during subjective night. Real-time PCR using the SCN, paraventricular nucleus and cortex confirmed these results. Next, we analyzed the expression of the Dexras1 gene in the SCN of cryptochrome (Cry) 1 and 2 double knockout mice. We found that the rhythmic expression disappeared. The results indicate that Dexras1 rhythmicity and levels are dependent upon CRYs. This is the first time that the G protein, which may be involved in the input pathway, has been isolated as a cycling gene in the SCN.
Takahashi
Hirokazu
H
Transcriptome Profiling Group, National Institute of Radiological Sciences, Anagawa 4-9-1, Inage-ku, Chiba 263-8555, Japan.
Umeda
Nanae
N
Tsutsumi
Yoko
Y
Fukumura
Ryutaro
R
Ohkaze
Hajime
H
Sujino
Mitsugu
M
van der Horst
Gijsbertus
G
Yasui
Akira
A
Inouye
Shin-Ichi T
ST
Fujimori
Akira
A
Ohhata
Tatsuya
T
Araki
Ryoko
R
Abe
Masumi
M
D000818:Animals; D002940:Circadian Rhythm / Q000235:genetics*; D056931:Cryptochromes; D003907:Dexamethasone; D029721:Drosophila Proteins; D005136:Eye Proteins; D005420:Flavoproteins / Q000235:genetics; D019204:GTP-Binding Proteins; D005786:Gene Expression Regulation; D017403:In Situ Hybridization; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D020559:Monomeric GTP-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D017956:Photoreceptor Cells, Invertebrate; D016133:Polymerase Chain Reaction / Q000379:methods; D012333:RNA, Messenger / Q000032:analysis; D043562:Receptors, G-Protein-Coupled; D013493:Suprachiasmatic Nucleus / Q000502:physiology*; D018631:ras Proteins
D056931:Cryptochromes; D029721:Drosophila Proteins; D005136:Eye Proteins; D005420:Flavoproteins; D012333:RNA, Messenger; D043562:Receptors, G-Protein-Coupled; C119828:cry protein, Drosophila; D003907:Dexamethasone; D019204:GTP-Binding Proteins; C498511:Rasd1 protein, mouse; D020559:Monomeric GTP-Binding Proteins; D018631:ras Proteins