Purchase this article with an account.
P.M. Iuvone, S.S. Chaurasia, C.R. Jackson, N. Pozdeyev, R. Haque; Diurnal and Circadian Expression of Ca2+/Calmodulin–Stimulated Adenylyl Cyclases in Retina of C57Bl/6J Mice . Invest. Ophthalmol. Vis. Sci. 2006;47(13):5426.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Cyclic AMP (cAMP) levels in photoreceptor cells are high in darkness, reduced by light exposure, and subject to regulation by retinal circadian clocks. The present study was conducted to determine if the expression of genes encoding the Ca2+/calmodulin–stimulated adenylyl cyclases, AC1, AC3, and AC8, is regulated in a circadian or diurnal fashion in the mouse retina.
Mice were entrained to a 12h light / 12h dark cycle (LD) for at least two weeks and were then kept in constant (24 h / day) darkness (DD) for two days. Retinas were dissected at various times on the last day of LD and the second day of DD. Transcripts encoding AC1, AC3 and AC8 were quantified by real–time RT–PCR. Adenylyl cyclase activity in retinal membranes was determined by measuring the conversion of [32P]ATP to [32P]cAMP.
The expression of Ac1, Ac3 and Ac8 transcripts in retina increased during the daytime, peaking ∼4 hours after light onset in the LD cycle, and were comparatively low during the night. When mice were kept in DD for 2 days, Ac1 mRNA levels continued to follow a similar rhythmic pattern, suggesting circadian clock control of expression. In contrast, expression of Ac3 and Ac8 was arrhythmic in DD. Ca2+/calmodulin–stimulated adenylyl cyclase activity in retinal membranes was also rhythmic, with high levels at night and low levels during the day.
The mouse retina expresses diurnal and circadian rhythms of Ac1, Ac3, and Ac8 transcript levels and of Ca2+/calmodulin–stimulated adenylyl cyclase activity. The rhythms of Ca2+/calmodulin–stimulated adenylyl cyclases provide a basis for the regulation of cAMP by the light–dark cycle and circadian clocks.
This PDF is available to Subscribers Only