In vivo imaging of clock gene expression in multiple tissues of freely moving mice.
Clock genes are expressed throughout the body, although how they oscillate in unrestrained animals is not known. Here, we show an in vivo imaging technique that enables long-term simultaneous imaging of multiple tissues. We use dual-focal 3D tracking and signal-intensity calibration to follow gene expression in a target area. We measure circadian rhythms of clock genes in the olfactory bulb, right and left ears and cortices, and the skin. In addition, the kinetic relationship between gene expression and physiological responses to experimental cues is monitored. Under stable conditions gene expression is in phase in all tissues. In response to a long-duration light pulse, the olfactory bulb shifts faster than other tissues. In Cry1(-/-) Cry2(-/-) arrhythmic mice circadian oscillation is absent in all tissues. Thus, our system successfully tracks circadian rhythms in clock genes in multiple tissues in unrestrained mice.
Department of Applied Molecular-Imaging Physics, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan.
Toshiyuki
T
Hamada
Department of Medical Physics and Engineering, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan.
Kenneth
K
Sutherland
Department of Applied Molecular-Imaging Physics, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan.|Department of Medical Physics and Engineering, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan.|Department of Biomedical Science and Engineering, Hokkaido University Graduate School of Health Science, Sapporo 062-0812, Japan.|Global Station for Quantum Medical Science and Engineering, Global Institution for Collaborative Research and Education (GI-CoRE), Hokkaido University, Sapporo 060-8638, Japan.
Masayori
M
Ishikawa
Department of Medical Physics and Engineering, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan.
Naoki
N
Miyamoto
Department of Chronomedicine, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan.
Sato
S
Honma
Global Station for Quantum Medical Science and Engineering, Global Institution for Collaborative Research and Education (GI-CoRE), Hokkaido University, Sapporo 060-8638, Japan.|Department of Radiation Medicine, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan.
Hiroki
H
Shirato
Department of Chronomedicine, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan.
Ken-Ichi
K
Honma
D000818:Animals; D056926:CLOCK Proteins / Q000235:genetics* / Q000378:metabolism; D002940:Circadian Rhythm / Q000235:genetics / Q000528:radiation effects; D049454:Firefly Luciferin / Q000378:metabolism; D005786:Gene Expression Regulation / Q000528:radiation effects; D008027:Light; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D057054:Molecular Imaging; D009068:Movement; D009928:Organ Specificity / Q000235:genetics*
D049454:Firefly Luciferin; D056926:CLOCK Proteins