Expression of circadian clock genes in retinal dopaminergic cells.
The mammalian neural retina contains single or multiple intrinsic circadian oscillators that can be directly entrained by light cycles. Dopaminergic amacrine (DA) cells represent an especially interesting candidate as a site of the retinal oscillator because of the crucial role of dopamine in light adaptation, and the widespread distribution of dopamine receptors in the retina. We hereby show by single-cell, end-point RT-PCR that retinal DA cells contain the transcripts for six core components of the circadian clock: Bmal1, Clock, Cry1, Cry2, Per1, and Per2. Rod photoreceptors represented a negative control, because they did not appear to contain clock transcripts. We finally confirmed that DA cells contain the protein encoded by the Bmal1 gene by comparing immunostaining of the nuclei of DA cells in the retinas of wildtype and Bmal1-/- mice. It is therefore likely that DA cells contain a circadian clock that anticipates predictable variations in retinal illumination.
Dorenbos
Ronald
R
Department of Neurobiology, Harvard Medical School, Boston, Massachusetts 02115, USA.
Contini
Massimo
M
Hirasawa
Hajime
H
Gustincich
Stefano
S
Raviola
Elio
E
D000818:Animals; D002940:Circadian Rhythm / Q000235:genetics*; D004298:Dopamine / Q000502:physiology*; D004587:Electrophoresis, Agar Gel; D006801:Humans; D007150:Immunohistochemistry; D007438:Introns / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D012160:Retina / Q000166:cytology* / Q000502:physiology*; D051245:Retinal Bipolar Cells / Q000378:metabolism / Q000502:physiology; D017948:Retinal Rod Photoreceptor Cells / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction
D004298:Dopamine