Visual receptor cycle in normal and <i>period</i> mutant <i>Drosophila</i>: Microspectrophotometry, electrophysiology, and ultrastructural morphometry

Chen, De‐Mao; Christianson, J. Scott; Sapp, Randall; Stark, William S.

doi:10.1017/s0952523800009585

Cited by 60 publications

(46 citation statements)

References 39 publications

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“…Moreover, we studied the optomotor and phototactic behavior of cry 01 flies or flies in which dCRY lacked the C terminus tail (cry M ) (5). Wild-type flies are known to show a diurnal rhythm in visual sensitivity determined by ERG recordings, with maximal sensitivity in the first half of the night (28). A comparable rhythm was found in control flies [Canton S (CS) × w 1118 ] with a pronounced sensitivity and a maximum in the middle of the night (Fig.…”

Section: Resultsmentioning

confidence: 52%

Fly cryptochrome and the visual system

Mazzotta

Rossi

Leonardi

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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Cryptochromes are flavoproteins, structurally and evolutionarily related to photolyases, that are involved in the development, magnetoreception, and temporal organization of a variety of organisms. Drosophila CRYPTOCHROME (dCRY) is involved in light synchronization of the master circadian clock, and its C terminus plays an important role in modulating light sensitivity and activity of the protein. The activation of dCRY by light requires a conformational change, but it has been suggested that activation could be mediated also by specific "regulators" that bind the C terminus of the protein. This C-terminal region harbors several protein-protein interaction motifs, likely relevant for signal transduction regulation. Here, we show that some functional linear motifs are evolutionarily conserved in the C terminus of cryptochromes and that class III PDZ-binding sites are selectively maintained in animals. A coimmunoprecipitation assay followed by mass spectrometry analysis revealed that dCRY interacts with Retinal Degeneration A (RDGA) and with Neither Inactivation Nor Afterpotential C (NINAC) proteins. Both proteins belong to a multiprotein complex (the Signalplex) that includes visualsignaling molecules. Using bioinformatic and molecular approaches, dCRY was found to interact with Neither Inactivation Nor Afterpotential C through Inactivation No Afterpotential D (INAD) in a light-dependent manner and that the CRY-Inactivation No Afterpotential D interaction is mediated by specific domains of the two proteins and involves the CRY C terminus. Moreover, an impairment of the visual behavior was observed in fly mutants for dCRY, indicative of a role, direct or indirect, for this photoreceptor in fly vision.

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Section: Resultsmentioning

confidence: 52%

Fly cryptochrome and the visual system

Mazzotta

Rossi

Leonardi

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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“…Otherwise, it would be impossible to measure increasing and decreasing irradiances during dawn and dusk. The observed clock protein oscillations in the photoreceptor cells of the compound eyes might regulate light sensitivity of the circadian system (25). If true, the clock protein levels and oscillations should not be altered by dim light, and the high sensitivity of the clock during early dawn and late dusk should be preserved.…”

Section: Discussionmentioning

confidence: 97%

Moonlight shifts the endogenous clock of Drosophila melanogaster

Bachleitner

Kempinger

Wülbeck

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

120

133

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The ability to be synchronized by light-dark cycles is a fundamental property of circadian clocks. Although there are indications that circadian clocks are extremely light-sensitive and that they can be set by the low irradiances that occur at dawn and dusk, this has not been shown on the cellular level. Here, we demonstrate that a subset of Drosophila's pacemaker neurons responds to nocturnal dim light. At a nighttime illumination comparable to quartermoonlight intensity, the flies increase activity levels and shift their typical morning and evening activity peaks into the night. In parallel, clock protein levels are reduced, and clock protein rhythms shift in opposed direction in subsets of the previously identified morning and evening pacemaker cells. No effect was observed on the peripheral clock in the eye. Our results demonstrate that the neurons driving rhythmic behavior are extremely light-sensitive and capable of shifting activity in response to the very low light intensities that regularly occur in nature. This sensitivity may be instrumental in adaptation to different photoperiods, as was proposed by the morning and evening oscillator model of Pittendrigh and Daan. We also show that this adaptation depends on retinal input but is independent of cryptochrome.circadian rhythm ͉ dual-oscillator model ͉ PERIOD ͉ synchronization ͉ TIMELESS E ndogenous circadian clocks prepare organisms according to the most reliable and predictable of environmental changes, the cycle of day and night. To function as reliable timers, circadian clocks themselves are synchronized to the 24-h cycle. This synchronization is accomplished mainly by light. Whereas light during the day has little effect on circadian clocks, they are most susceptible to light in the early and late night. Bright light pulses applied during the early night delay the phase of the clock; light pulses during the late night advance it (1). Stable synchronization occurs when the delaying and advancing effects of light on the clock in the early (at dusk) and late night (at dawn) are of equal strength. In nature, stable synchronization is a challenging task, because irradiances during dawn and dusk can vary largely from day to day because of the weather. Bünning (2) measured irradiances systematically throughout day and night and found that day-to-day fluctuations are smallest during early dawn and late dusk, when the irradiances are still Ͻ10 lux. Therefore, he proposed that organisms time their clocks to the very low irradiances occurring during early dawn and late dusk and thus must be very light-sensitive. Indeed, he found that bean plants synchronize to light of moonlight intensity (0.6-0.8 lux) and that artificial moonlight applied during the night phase shifted the rhythm of leaf movement (2). Bean plants lower their leaves during the night, and Bünning suggested that they need to do so to decrease the moonlight reaching the leaf surface to avoid their light-sensitive clocks interpreting the moonlight as the coming dawn (2).In animals, it is under deb...

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“…Dytiscus, (Jahn and Wulff, 1943), butterflies (Swihart, 1963), Drosophila (Chen et al, 1992), cockroach (Wills et al, 1985)]. There is an increase in sensitivity at night in the locust Valanga (Horridge et al, 1981).…”

Section: Discussionmentioning

confidence: 99%

Solitary and Gregarious Locusts Differ in Circadian Rhythmicity of a Visual Output Neuron

et al. 2012

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Locusts demonstrate remarkable phenotypic plasticity driven by changes in population density. This density dependent phase polyphenism is associated with many physiological, behavioural and morphological changes, including observations that cryptic solitarious (solitary-reared) individuals start to fly at dusk, whereas gregarious (crowd-reared) individuals are day-active. We have recorded for 24-36h from an identified visual output neuron, the descending contralateral movement detector (DCMD) of Schistocerca gregaria, in solitarious and gregarious animals. DCMD signals impending collision and participates in flight avoidance manoeuvres. The strength of DCMD's response to looming stimuli, characterised by the number of evoked spikes and peak firing rate, varies approximately sinusoidally with a period close to 24h under constant light in solitarious locusts. In gregarious individuals the 24h pattern is more complex, being modified by secondary ultradian rhythms. DCMD's strongest responses occur around expected dusk in solitarious locusts, but up to 6h earlier in gregarious locusts, matching the times of day at which locusts of each type are most active. We thus demonstrate a neuronal correlate of a temporal shift in behaviour that is observed in gregarious locusts. Our ability to alter the nature of a circadian rhythm by manipulating the rearing density of locusts under identical light-dark cycles may provide important tools to investigate further the mechanisms underlying diurnal rhythmicity.

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Visual receptor cycle in normal and period mutant Drosophila: Microspectrophotometry, electrophysiology, and ultrastructural morphometry

Cited by 60 publications

References 39 publications

Fly cryptochrome and the visual system

Fly cryptochrome and the visual system

Moonlight shifts the endogenous clock of Drosophila melanogaster

Solitary and Gregarious Locusts Differ in Circadian Rhythmicity of a Visual Output Neuron

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