Effects of a Clock Mutation on the Subjective Day — Implications for a Membrane Model of the Drosophila Circadian Clock

Konopka, Ronald J.; Orr, Dominic

doi:10.1007/978-1-4684-7968-3_29

Cited by 20 publications

(8 citation statements)

References 4 publications

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“…These observations have three related implications. First, the enhanced effects of LL in the mutant genotype are consistent with previous observations of greater light sensitivity of the per5 strain (Handler and Konopka, 1979;Konopka and Orr, 1980;Konopka et al, 1989;Saunders et al, 1994) and suggest that PER, in addition to TIM, is participating in the light response. Second, the similar enhanced effect of LL on the PER-S profile and pers RNA profile suggests that these two responses are mechanistically related.…”

Section: Effect Of Constant Light On the Wild-type Cyclesupporting

confidence: 88%

“…Yet the mutants entrain well to 24 h LD cycles (Hamblin-Coyle et al, 1992). The rhythmicity of pers flies is also reported to be more light-sensitive than that of wild-type flies (Handler and Konopka, 1979;Konopka and Orr, 1980;Konopka et al, 1989;Saunders et al, 1994). Taken together, these two effects of light suggest that constant light treatment might be revealing about the relationship of the two protein cycles to the RNA cycles and about the mechanism of light entrainment.…”

Section: Effect Of Constant Light On the Wild-type Cyclementioning

confidence: 93%

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Effect of constant light and circadian entrainment of perS flies: evidence for light-mediated delay of the negative feedback loop in Drosophila.

1996

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Light is the dominant environmental cue that provides temporal information to circadian pacemakers. In Drosophila melanogaster some period gene mutants have altered free‐running circadian periods but entrain to 24 h light‐dark cycles. To address the mechanism of light entrainment in Drosophila, we examined the effects of constant light on the period gene (per) and timeless gene (tim) products in wild‐type and perS flies. The results indicate that light affects three features of the PER‐TIM program: PER and TIM phosphorylation, PER and TIM accumulation, and per and tim RNA cycling. A post‐transcriptional effect on the PER‐TIM complex is the likely primary clock target, which then delays the subsequent decrease in per and tim RNA levels. This is consistent with a negative feedback loop, in which the PER‐TIM complex contributes to the decrease in per and tim RNA levels, presumably at the transcriptional level. There are enhanced constant light effects on the perS mutant, which further support negative feedback as well as support its importance to entrainment of these flies to a 24 h cycle, far from their intrinsic period of 19 h. The perS mutant leads to a truncated protein accumulation phase and a subsequent premature perS RNA increase. A standard 24 h light‐dark cycle delays the negative feedback circuit and extends the RNA and protein profiles, compensating for the accelerated RNA increase and restoring the rhythms to wild‐type‐like periodicity.

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Section: Effect Of Constant Light On the Wild-type Cyclesupporting

confidence: 88%

Section: Effect Of Constant Light On the Wild-type Cyclementioning

confidence: 93%

Effect of constant light and circadian entrainment of perS flies: evidence for light-mediated delay of the negative feedback loop in Drosophila.

1996

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“…At this point, some of the findings from measuring rhythms of locomotor behavior are more interesting. Here, Konopka & Orr (1980) showed that the duration of the active part of per s 's cycle is only 8 h instead of 12 (the latter value being characteristic of wild-type adults). Yet, the 12 h 'rest' part of the cycle is the same in flies of both genotypes.…”

Section: (C) Mutations Affecting Biological Oscillationsmentioning

confidence: 93%

Genetics of the nervous system inDrosophila

Hall

1982

Quart. Rev. Biophys.

173

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“…Also, phase advances and delays of eclosion peaks, induced during subjective night, are larger than in wild-type (Konopka 1979). These data led to a "membrane model" of circadian rhythm control by the product of this Drosophila gene (Konopka & Orr 1980); the ideas here are similar to the "ionic fl ux" formalisms developed more generally to model circadian clocks (Engel mann & Schrempf 1980). However, the molecular data extant on the per gene product (see below) do not yet give further force to this kind of clock model.…”

Section: Drosophila Clock Mutantsmentioning

confidence: 85%

“…For example, essentially the entirety of the tau-shortening effects of the frq2, frq4, and frq6 mutations can be accounted for by the fact that the middle-to-1a te subset of the 1ight insensitive half of a free-running cycle is but 65% of normal (Feldman 1985). A similarity to Drosophila's per' mutant is evident (cf Konopka & Orr 1980).…”

Section: Drosophila Clock Mutantsmentioning

confidence: 99%