Shell neurons of the master circadian clock coordinate the phase of tissue clocks throughout the brain and body

BMC Biology

Research Article

Timothy J. Bartness¹  Brett J. W. Teubner²  Ian Kloehn³  Jennifer A. Evans³  Ben L. Callif³  Kimberly M. Baker³  Tanya Leise⁴  Oscar Castanon-Cervantes⁵  Ketema N. Paul⁵  Alec J. Davidson⁵  Andrew S. Mitchell⁵  J. Christopher Ehlen⁵  Ting-Chung Suen⁵  Gianluca Tosini⁶  Kenkichi Baba⁶ 

[1] Department of Biology and Center for Obesity Reversal, Georgia State University, 30302, Atlanta, GA, USA;Department of Biology and Center for Obesity Reversal, Georgia State University, 30302, Atlanta, GA, USA;Department of Developmental Neurobiology, St. Jude Children’s Research Hospital, 38105, Memphis, TN, USA;Department of Biomedical Sciences, Marquette University, 53233, Milwaukee, WI, USA;Department of Mathematics and Statistics, Amherst College, 01002, Amherst, MA, USA;Department of Neurobiology, Morehouse School of Medicine, 30310, Atlanta, GA, USA;Department of Pharmacology, Morehouse School of Medicine, 30310, Atlanta, GA, USA;

关键词: Circadian;    Coupling;    Peripheral and central oscillators;    Photoperiod;    Suprachiasmatic nucleus;   

DOI  :  10.1186/s12915-015-0157-x

 received in 2015-03-11, accepted in 2015-06-16,  发布年份 2015

来源: Springer

【 摘 要 】

BackgroundDaily rhythms in mammals are programmed by a master clock in the suprachiasmatic nucleus (SCN). The SCN contains two main compartments (shell and core), but the role of each region in system-level coordination remains ill defined. Herein, we use a functional assay to investigate how downstream tissues interpret region-specific outputs by using in vivo exposure to long day photoperiods to temporally dissociate the SCN. We then analyze resulting changes in the rhythms of clocks located throughout the brain and body to examine whether they maintain phase synchrony with the SCN shell or core.ResultsNearly all of the 17 tissues examined in the brain and body maintain phase synchrony with the SCN shell, but not the SCN core, which indicates that downstream oscillators are set by cues controlled specifically by the SCN shell. Interestingly, we also found that SCN dissociation diminished the amplitude of rhythms in core clock gene and protein expression in brain tissues by 50–75 %, which suggests that light-driven changes in the functional organization of the SCN markedly influence the strength of rhythms in downstream tissues.ConclusionsOverall, our results reveal that body clocks receive time-of-day cues specifically from the SCN shell, which may be an adaptive design principle that serves to maintain system-level phase relationships in a changing environment. Further, we demonstrate that lighting conditions alter the amplitude of the molecular clock in downstream tissues, which uncovers a new form of plasticity that may contribute to seasonal changes in physiology and behavior.

【 授权许可】

CC BY   
© Evans et al. 2015