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Circadian and ultradian rhythms of clock gene expression in the suprachiasmatic nucleus of freely moving mice.

Ono D, Honma K, Honma S - Sci Rep (2015)

Bottom Line: We found robust circadian rhythms in the clock gene expression, the phase-relation of which were the same as those observed ex vivo.Episodic bursts often accompanied activity bouts, but stoichiometric as well as temporal analyses revealed no causality between them.Clock gene expression in the SCN in vivo is regulated by the circadian pacemaker and ultradian rhythms of unknown origin.

View Article: PubMed Central - PubMed

Affiliation: Photonic Bioimaging Section, Research Center for Cooperative Projects, Hokkaido University Graduate School of Medicine, Sapporo, 060-8638, Japan.

ABSTRACT
In mammals, the temporal order of physiology and behavior is primarily regulated by the circadian pacemaker located in the hypothalamic suprachiasmatic nucleus (SCN). Rhythms are generated in cells by an auto-regulatory transcription/translation feedback loop, composed of several clock genes and their protein products. Taking advantage of bioluminescence reporters, we have succeeded in continuously monitoring the expression of clock gene reporters Per1-luc, PER2::LUC and Bmal1-ELuc in the SCN of freely moving mice for up to 3 weeks in constant darkness. Bioluminescence emitted from the SCN was collected with an implanted plastic optical fiber which was connected to a cooled photomultiplier tube. We found robust circadian rhythms in the clock gene expression, the phase-relation of which were the same as those observed ex vivo. The circadian rhythms were superimposed by episodic bursts which had ultradian periods of approximately 3.0 h. Episodic bursts often accompanied activity bouts, but stoichiometric as well as temporal analyses revealed no causality between them. Clock gene expression in the SCN in vivo is regulated by the circadian pacemaker and ultradian rhythms of unknown origin.

No MeSH data available.


Related in: MedlinePlus

Episodic bursts of reporter bioluminescence and activity bouts in vivo(a, d, g) Representative episodic fluctuations of reporter bioluminescence (colored traces) and simultaneously measured activity bouts (black traces) in freely moving mice for 5 consecutive days (a, Per1-luc; d, PER2::LUC; g, Bmal1-ELuc). Raw data (non-deterended, non-smoothed) are plotted in 5 min bins. (b, e ,h) Wavelet spectrum is illustrated for episodic bursts of bioluminescence (upper) and for activity bout (lower) in the ultradian range (0-12 h). The intensity of rhythm at a particular period was expressed with different colors. Dark red indicates the intensity larger than 1.5 time of the individual mean peak level of bioluminescence burst (Fig. 4). Intensities below this level are expressed by different colors down to dark blue. (c, f, i) Chi square periodograms in the circadian (upper) and ultradian ranges (lower) are illustrated for bioluminescence (left) and behavior activity (right) in each clock gene with the same colors as in the actogram. An oblique line in each periodogram represents a significance level (p < 0.05).
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f2: Episodic bursts of reporter bioluminescence and activity bouts in vivo(a, d, g) Representative episodic fluctuations of reporter bioluminescence (colored traces) and simultaneously measured activity bouts (black traces) in freely moving mice for 5 consecutive days (a, Per1-luc; d, PER2::LUC; g, Bmal1-ELuc). Raw data (non-deterended, non-smoothed) are plotted in 5 min bins. (b, e ,h) Wavelet spectrum is illustrated for episodic bursts of bioluminescence (upper) and for activity bout (lower) in the ultradian range (0-12 h). The intensity of rhythm at a particular period was expressed with different colors. Dark red indicates the intensity larger than 1.5 time of the individual mean peak level of bioluminescence burst (Fig. 4). Intensities below this level are expressed by different colors down to dark blue. (c, f, i) Chi square periodograms in the circadian (upper) and ultradian ranges (lower) are illustrated for bioluminescence (left) and behavior activity (right) in each clock gene with the same colors as in the actogram. An oblique line in each periodogram represents a significance level (p < 0.05).

Mentions: Circadian rhythms in clock gene expression were observed continuously for up to 3 weeks in the SCN of freely moving mice, carrying bioluminescence reporters for the expression of Per1 (Per1-luc), Bmal1 (Bmal1-ELuc) or for the protein product of Per2 (PER2::LUC) (Fig. 1, Fig. 2, Supplementary Figure S1, Figure S2). Histological examination revealed that the tip of an implanted optical fiber was located at the dorsal border of the SCN in most cases and was found within the dorsal part of the SCN in the rest of cases (Supplementary Figure S1c).


Circadian and ultradian rhythms of clock gene expression in the suprachiasmatic nucleus of freely moving mice.

Ono D, Honma K, Honma S - Sci Rep (2015)

Episodic bursts of reporter bioluminescence and activity bouts in vivo(a, d, g) Representative episodic fluctuations of reporter bioluminescence (colored traces) and simultaneously measured activity bouts (black traces) in freely moving mice for 5 consecutive days (a, Per1-luc; d, PER2::LUC; g, Bmal1-ELuc). Raw data (non-deterended, non-smoothed) are plotted in 5 min bins. (b, e ,h) Wavelet spectrum is illustrated for episodic bursts of bioluminescence (upper) and for activity bout (lower) in the ultradian range (0-12 h). The intensity of rhythm at a particular period was expressed with different colors. Dark red indicates the intensity larger than 1.5 time of the individual mean peak level of bioluminescence burst (Fig. 4). Intensities below this level are expressed by different colors down to dark blue. (c, f, i) Chi square periodograms in the circadian (upper) and ultradian ranges (lower) are illustrated for bioluminescence (left) and behavior activity (right) in each clock gene with the same colors as in the actogram. An oblique line in each periodogram represents a significance level (p < 0.05).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4508664&req=5

f2: Episodic bursts of reporter bioluminescence and activity bouts in vivo(a, d, g) Representative episodic fluctuations of reporter bioluminescence (colored traces) and simultaneously measured activity bouts (black traces) in freely moving mice for 5 consecutive days (a, Per1-luc; d, PER2::LUC; g, Bmal1-ELuc). Raw data (non-deterended, non-smoothed) are plotted in 5 min bins. (b, e ,h) Wavelet spectrum is illustrated for episodic bursts of bioluminescence (upper) and for activity bout (lower) in the ultradian range (0-12 h). The intensity of rhythm at a particular period was expressed with different colors. Dark red indicates the intensity larger than 1.5 time of the individual mean peak level of bioluminescence burst (Fig. 4). Intensities below this level are expressed by different colors down to dark blue. (c, f, i) Chi square periodograms in the circadian (upper) and ultradian ranges (lower) are illustrated for bioluminescence (left) and behavior activity (right) in each clock gene with the same colors as in the actogram. An oblique line in each periodogram represents a significance level (p < 0.05).
Mentions: Circadian rhythms in clock gene expression were observed continuously for up to 3 weeks in the SCN of freely moving mice, carrying bioluminescence reporters for the expression of Per1 (Per1-luc), Bmal1 (Bmal1-ELuc) or for the protein product of Per2 (PER2::LUC) (Fig. 1, Fig. 2, Supplementary Figure S1, Figure S2). Histological examination revealed that the tip of an implanted optical fiber was located at the dorsal border of the SCN in most cases and was found within the dorsal part of the SCN in the rest of cases (Supplementary Figure S1c).

Bottom Line: We found robust circadian rhythms in the clock gene expression, the phase-relation of which were the same as those observed ex vivo.Episodic bursts often accompanied activity bouts, but stoichiometric as well as temporal analyses revealed no causality between them.Clock gene expression in the SCN in vivo is regulated by the circadian pacemaker and ultradian rhythms of unknown origin.

View Article: PubMed Central - PubMed

Affiliation: Photonic Bioimaging Section, Research Center for Cooperative Projects, Hokkaido University Graduate School of Medicine, Sapporo, 060-8638, Japan.

ABSTRACT
In mammals, the temporal order of physiology and behavior is primarily regulated by the circadian pacemaker located in the hypothalamic suprachiasmatic nucleus (SCN). Rhythms are generated in cells by an auto-regulatory transcription/translation feedback loop, composed of several clock genes and their protein products. Taking advantage of bioluminescence reporters, we have succeeded in continuously monitoring the expression of clock gene reporters Per1-luc, PER2::LUC and Bmal1-ELuc in the SCN of freely moving mice for up to 3 weeks in constant darkness. Bioluminescence emitted from the SCN was collected with an implanted plastic optical fiber which was connected to a cooled photomultiplier tube. We found robust circadian rhythms in the clock gene expression, the phase-relation of which were the same as those observed ex vivo. The circadian rhythms were superimposed by episodic bursts which had ultradian periods of approximately 3.0 h. Episodic bursts often accompanied activity bouts, but stoichiometric as well as temporal analyses revealed no causality between them. Clock gene expression in the SCN in vivo is regulated by the circadian pacemaker and ultradian rhythms of unknown origin.

No MeSH data available.


Related in: MedlinePlus