Circadian clock locus frequency: protein encoded by a single open reading frame defines period length and temperature compensation.

Aronson, Benjamin D.; Johnson, Keith A.; Dunlap, Jay C.

doi:10.1073/pnas.91.16.7683

Cited by 206 publications

(202 citation statements)

References 28 publications

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“…The first FLO was identified two decades ago in frq-null strains where sometimes rhythmic banding would develop after several days' growth on race tubes (21,25). Later, oscillations of gene expression, diacylglycerol levels, development, or nitrate reductase activity were found in either frq-null or wc-1-null strains (43)(44)(45).…”

Section: Discussionmentioning

confidence: 99%

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A developmental cycle masks output from the circadian oscillator under conditions of choline deficiency in Neurospora

Shi

Larrondo²,

Loros³

et al. 2007

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

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In Neurospora, metabolic oscillators coexist with the circadian transcriptional/translational feedback loop governed by the FRQ (Frequency) and WC (White Collar) proteins. One of these, a choline deficiency oscillator (CDO) observed in chol-1 mutants grown under choline starvation, drives an uncompensated long-period developmental cycle (Ϸ60 -120 h). To assess possible contributions of this metabolic oscillator to the circadian system, molecular and physiological rhythms were followed in liquid culture under choline starvation, but these only confirmed that an oscillator with a normal circadian period length can run under choline starvation. This finding suggested that long-period developmental cycles elicited by nutritional stress could be masking output from the circadian system, although a caveat was that the CDO sometimes requires several days to become consolidated. To circumvent this and observe both oscillators simultaneously, we used an assay using a codon-optimized luciferase to follow the circadian oscillator. Under conditions where the long-period, uncompensated, CDO-driven developmental rhythm was expressed for weeks in growth tubes, the luciferase rhythm in the same cultures continued in a typical compensated manner with a circadian period length dependent on the allelic state of frq. Periodograms revealed no influence of the CDO on the circadian oscillator. Instead, the CDO appears as a cryptic metabolic oscillator that can, under appropriate conditions, assume control of growth and development, thereby masking output from the circadian system. frqdriven luciferase as a reporter of the circadian oscillator may in this way provide a means for assessing prospective role(s) of metabolic and/or ancillary oscillators within cellular circadian systems.Frequency-less oscillator ͉ clock

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Section: Discussionmentioning

confidence: 99%

“…Strains lacking frq, wc-1, or wc-2 have defects in the clock and lose circadian regulation of conidiation under most conditions (21)(22)(23). Intriguingly, however, rhythms of conidiation, metabolic regulation, and gene expression can still be observed under certain conditions in the absence of the FWO (reviewed in refs.…”

mentioning

confidence: 99%

A developmental cycle masks output from the circadian oscillator under conditions of choline deficiency in Neurospora

Shi

Larrondo²,

Loros³

et al. 2007

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

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Section: Ircadian Rhythms Are Biological Rhythms Withmentioning

confidence: 99%

“…Point mutations in the frq gene can increase or decrease the period of the conidiation rhythm (Feldman and Hoyle 1973;Aronson et al 1994). Null mutations at the frq locus, either a point mutation (Loros and Feldman 1986) or a complete deletion of the coding sequence (Aronson et al 1994), show a residual rhythm that lacks temperature compensation. Wc-1 and wc-2 mutants were originally isolated as ''blind'' mutants and do not display conidiation banding under ordinary laboratory conditions (Degli-Innocenti and Russo 1984;Crosthwaite et al 1997).…”

Section: Ircadian Rhythms Are Biological Rhythms Withmentioning

confidence: 99%

Rhythmic Conidiation in Constant Light inVividMutants ofNeurospora crassa

et al. 2009

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“…As these mutants all contain deletions of the noted gene (Aronson et al 1994;Collett et al 2002), with frq 10 and wc-2D expressing very low levels of WC-1 and FRQ, respectively (Lee et al 2000;Collett et al 2002), the observation of banding in these strains suggests the presence of an alternate oscillator (or oscillators) that was prompted to action by the addition of farnesol or geraniol or by alteration in lipid biosynthesis. Additional observations about the presence of alternate oscillators can be found in recent articles (Bell-Pedersen et al 2005;dePaula et al 2006;LakinThomas 2006) as well as in previous articles (Loros and Feldman 1986;Merrow et al 1999).…”

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confidence: 99%

Circadian Rhythms in Neurospora crassa: Clock Mutant Effects in the Absence of a frq-Based Oscillator

et al. 2007

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In Neurospora, the circadian rhythm is expressed as rhythmic conidiation driven by a feedback loop involving the protein products of frq (frequency), wc-1 (white collar-1), and wc-2, known as the frq/wc (FWC) oscillator. Although strains carrying null mutations such as frq 10 or wc-2D lack a functional FWC oscillator and do not show a rhythm under most conditions, a rhythm can be observed in them by the addition of geraniol or farnesol to the media. Employing this altered media as an assay, the effect of other clock mutations in a frq 10 -or wc-2D-null background can be measured. It was found that the existing clock mutations fall into three classes: (1) those, such as prd-3 or prd-4 or frq 1 , that showed no effect in a clock null background; (2) those, such as prd-1 or prd-2 or prd-6, that did have a measurable effect in the frq 10 background; and (3) those, such as the new mutation ult, that suppressed the frq 10 or wc-2D effect, i.e., geraniol/farnesol was not required for a visible rhythm. This classification suggests that some of the known clock mutations are part of a broader multioscillator system.

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Circadian clock locus frequency: protein encoded by a single open reading frame defines period length and temperature compensation.

Abstract: Circadian rhythms are a nearly ubiquitous feature of eukaryotic organisms. Daily fluctuations in physiological and biochemical parameters driven by the circadian clock include cell division, locomotor activity in animals, and photosynthesis and leafmovement in plants (for review, see ref.

Cited by 206 publications

References 28 publications

A developmental cycle masks output from the circadian oscillator under conditions of choline deficiency in Neurospora

A developmental cycle masks output from the circadian oscillator under conditions of choline deficiency in Neurospora

Rhythmic Conidiation in Constant Light inVividMutants ofNeurospora crassa

Circadian Rhythms in Neurospora crassa: Clock Mutant Effects in the Absence of a frq-Based Oscillator

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