Local photic entrainment of the retinal circadian oscillator in the absence of rods, cones, and melanopsin.
Synchronization of the mammalian master circadian pacemaker to the daily light/dark cycle is mediated exclusively through retinal photoreceptors. The mammalian retina itself is also a self-sustained circadian oscillator. Here we report that the retinal molecular circadian clock can be entrained by lighting cycles in vitro, but that rods, cones, and melanopsin (Opn4) are not required for this entrainment. In vivo, retinas of Opn4(-/-);rd1/rd1 mice synchronize to light/dark cycles regardless of the phase of the master circadian pacemakers of the suprachiasmatic nuclei or the behavior of the animal. These data demonstrate that the retina uses a separate mechanism for local entrainment of its circadian clock than for entrainment of organism-level rhythmicity.
Departments of Ophthalmology.
Ethan D
ED
Buhr
Departments of Ophthalmology,Pathology, andBiological Structure, University of Washington, Seattle, WA 98104 russvg@uw.edu.
Russell N
RN
Van Gelder
D000818:Animals; D057906:Circadian Clocks / Q000502:physiology*; D002940:Circadian Rhythm / Q000502:physiology; D003624:Darkness; D015870:Gene Expression / Q000528:radiation effects; D008027:Light; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D051379:Mice; D057507:Mice, 129 Strain; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D009043:Motor Activity / Q000235:genetics / Q000502:physiology / Q000528:radiation effects; D056950:Period Circadian Proteins / Q000235:genetics / Q000378:metabolism; D012160:Retina / Q000166:cytology / Q000378:metabolism* / Q000528:radiation effects; D017949:Retinal Cone Photoreceptor Cells / Q000378:metabolism*; D017948:Retinal Rod Photoreceptor Cells / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017299:Rod Opsins / Q000235:genetics* / Q000378:metabolism; D013493:Suprachiasmatic Nucleus / Q000378:metabolism / Q000528:radiation effects; D000099210:Melanopsin
D008156:Luciferases; D056950:Period Circadian Proteins; D017299:Rod Opsins; D000099210:Melanopsin; C513312:Per2 protein, mouse
circadian rhythm