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Published on: September 27, 2012
Rhythmic expression of Nocturnin mRNA in multiple tissues of the mouse
Y Wang1, D L Osterbur, P L Megaw
1PEL-FREEZ Clinical Systems, LLC, 9099 North Deerbrook Trail, Brown Deer, WI 53223, USA. ywang@pel-freez.com
Background:
Nocturnin was originally identified by differential display as a circadian clock regulated gene with high expression at night in photoreceptors of the African clawed frog, Xenopus laevis. Although encoding a novel protein, the nocturnin cDNA had strong sequence similarity with a C-terminal domain of the yeast transcription factor CCR4, and with mouse and human ESTs. Since its original identification others have cloned mouse and human homologues of nocturnin/CCR4, and we have cloned a full-length cDNA from mouse retina, along with partial cDNAs from human, cow and chicken. The goal of this study was to determine the temporal pattern of nocturnin mRNA expression in multiple tissues of the mouse.
Results:
cDNA sequence analysis revealed a high degree of conservation among vertebrate nocturnin/CCR4 homologues along with a possible homologue in Drosophila. Northern analysis of mRNA in C3H/He and C57/Bl6 mice revealed that the mNoc gene is expressed in a broad range of tissues, with greatest abundance in liver, kidney and testis. mNoc is also expressed in multiple brain regions including suprachiasmatic nucleus and pineal gland. Furthermore, mNoc exhibits circadian rhythmicity of mRNA abundance with peak levels at the time of light offset in the retina, spleen, heart, kidney and liver.
Conclusion:
The widespread expression and rhythmicity of mNoc mRNA parallels the widespread expression of other circadian clock genes in mammalian tissues, and suggests that nocturnin plays an important role in clock function or as a circadian clock effector.
Insights
The mouse nocturnin (mNoc) gene is widely expressed across various tissues and shows circadian rhythmicity, suggesting its significant role in mammalian biological clocks. This finding highlights nocturnin
Area of Science:
- Molecular Biology
- Chronobiology
- Genetics
Background:
- Nocturnin (mNoc) identified as a circadian clock-regulated gene in Xenopus laevis photoreceptors.
- Homologues cloned in mouse and human, with sequence similarity to yeast CCR4.
- Full-length mouse cDNA cloned, prompting investigation into its expression patterns.
Purpose of the Study:
- To determine the temporal expression pattern of nocturnin mRNA in multiple mouse tissues.
- To investigate the conservation and tissue distribution of nocturnin.
- To assess the circadian rhythmicity of nocturnin mRNA abundance.
Main Methods:
- cDNA sequence analysis for homology.
- Northern blot analysis to detect mRNA expression in various mouse tissues.
- Analysis of temporal expression patterns and circadian rhythmicity.
Main Results:
- High conservation of nocturnin/CCR4 homologues across vertebrates and in Drosophila.
- Broad tissue expression of mNoc mRNA, with highest levels in liver, kidney, and testis.
- Circadian rhythmicity of mNoc mRNA observed in retina, spleen, heart, kidney, and liver, peaking at light offset.
Conclusions:
- Widespread expression and circadian rhythmicity of mNoc mRNA align with known circadian clock genes.
- Suggests nocturnin plays a crucial role in mammalian circadian clock function or acts as an effector.
- Highlights potential involvement of nocturnin in regulating physiological processes influenced by the biological clock.
