Differential effects of light and feeding on circadian organization of peripheral clocks in a forebrain Bmal1 mutant
- University of Texas Southwestern Medical Center, United States
- Northwestern University, United States
- University of Wisconsin, United States
- University of Tübingen, Germany
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, United States
Abstract
In order to assess the contribution of a central clock in the hypothalamic suprachiasmatic nucleus (SCN) to circadian behavior and the organization of peripheral clocks, we generated forebrain/SCN-specific Bmal1 knockout mice by using floxed Bmal1 and pan-neuronal Cre lines. The forebrain knockout mice showed >90% deletion of BMAL1 in the SCN and exhibited an immediate and complete loss of circadian behavior in constant conditions. Circadian rhythms in peripheral tissues persisted, but became desynchronized and damped in constant darkness. The loss of synchrony was rescued by light/dark cycles, and partially by restricted feeding (only in the liver and kidney but not in the other tissues) in a distinct manner. These results suggest that the forebrain/SCN is essential for internal temporal order of robust circadian programs in peripheral clocks and that individual peripheral clocks are affected differently by light and feeding in the absence of a functional oscillator in the forebrain.
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Ethics
Animal experimentation: All animal care and use procedures were in accordance with guidelines of the Northwestern University (Protocol 2006-0035) and UT Southwestern Institutional Animal Care and Use Committees (Protocols 2009-0054 and 2012-0090).
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© 2014, Izumo et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Differential effects of light and feeding on circadian organization of peripheral clocks in a forebrain Bmal1 mutant
eLife 3:e04617.
https://doi.org/10.7554/eLife.04617
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