The circadian output gene takeout is regulated by Pdp1ε

Abstract

The circadian clock controls many circadian outputs. Although a large number of transcripts are affected by the circadian oscillator, very little is known about their regulation and function. We show here that the Drosophila takeout gene, one of the output genes of the circadian oscillator, is regulated similarly to the circadian clock genes Clock (Clk) and cry. takeout RNA levels are at constant high levels in Clk JRK mutants. The circadian transcription factor PAR domain protein 1 (Pdp1ε) is a transcription factor that had previously been postulated to control clock output genes, particularly genes regulated similarly to Clk. In agreement with this, we show here that Pdp1ε is a regulator of takeout. Takeout levels are low in flies with reduced Pdp1ε and high in flies with increased amounts of Pdp1ε. Furthermore, flies with reduced or elevated Pdp1ε levels in the fat body display courtship defects, identifying Pdp1ε as an important transcriptional regulator in that tissue.fat body | courtship | clock | Drosophila G enetic and molecular analyses have yielded significant insight into the genes that constitute the core components of the Drosophila circadian clock (reviewed in refs. 1-3). It is regulated by two interlocked transcription/translation-based feedback loops, the period/timeless (per/tim) and Clock (Clk) loops (4). In addition, the regulation of the nuclear entry of proteins, their degradation rate, and phosphorylation state are crucial regulatory steps that are controlled by and contribute to the circadian clock. The per/tim cycle starts with the binding of CLK/CYC heterodimers to E-box promoter elements of the per and tim genes and their subsequent transcriptional activation. Eventually, the newly formed PER and TIM proteins will enter the nucleus and inhibit CLK/CYC action, thereby inhibiting the transcription of their own genes (5-7). Transcription of per and tim will resume once their protein levels have decreased sufficiently to release the inhibition of CLK/CYC. Rhythmic expression of Clock mRNA is regulated in the second loop, the Clock loop. CLK/CYC activate vrille (vri) and Pdp1ε, a transcriptional repressor and activator respectively, that have been shown to bind the Clock promoter competitively (8, 9). Although it was thought that this competition accounts for the oscillatory regulation of Clk mRNA, the fact that Clk mRNA levels are still high in Clk JRK mutants (4) and that the core oscillator is only minimally impacted in flies with increased or decreased PAR domain protein 1 (Pdp1ε) levels (depending on the allele/transgene and tissue examined) (10-12), indicate that an as yet unknown activator is required for Clk transcription. It has recently been demonstrated that CLK protein levels are constant in cells and that it is the phosphorylation state of the protein that determines its binding to DNA and its transcriptional activator function (7).Although locomotor activity is the best-characterized circadian output, the circadian clock regulates numerous other outputs such as sleep (13-16), n...

A novel gene from the takeout family involved in termite trail-following behavior

“…5A). The Drosophila takeout gene has been described as a circadian clockregulated output gene (McDonald and Rosbash, 2001;Benito et al, 2010). Specifically, takeout gene expression fluctuates with daily circadian rhythm patterns and is undetectable in circadian mutants, which suggests a role in circadian-associated functions .…”

“…Takeout and the related "moling" and "JP29" proteins found in Manduca sexta are all classified as hydrophobic ligand binding proteins (Touhara and Prestwich, 1992;Wojtasek and Prestwich, 1995;Shinoda et al, 1997;Saito et al, 2006;Robertson et al, 1999;Du et al, 2003;Hiruma and Riddiford, 2010). Expression of takeout mRNA in Drosophila is located in structures associated with feeding, specifically the head, cardia, crop, and antennae, and it has been linked to feeding behavior, food location, and longevity So et al, 2000;Wong et al, 2009;Gáliková and Flatt, 2010;Bauer et al, 2010;Benito et al, 2010). In Drosophila, starvation induces the expression of takeout mRNA; however, this process does not occur in mutants with disrupted circadian clocks, implying a link between takeout, circadian clocks, and the availability of nutrients .…”

Molecular Genetic Analysis of Circadian Timekeeping in Drosophila

“…Reducing, eliminating or increasing Pdp1 ε/δ expression abolishes behavioral rhythms (Benito et al, 2007; Zheng et al, 2009), which suggests that Pdp1 ε/δ controls output gene expression. Indeed, Pdp1 ε/δ controls rhythmic expression of takeout ( to ), which regulates courtship behavior (Dauwalder et al, 2002), but such regulation appears to be indirect as no canonical V/P-boxes are present near the to promoter (Benito et al, 2010). Although vri overexpression abolishes oscillator function due to repression of Clk transcription (Cyran et al, 2003; Glossop et al, 2003), it has not been possible to test whether vri is required for oscillator function because vri null mutants are lethal (Cyran et al, 2003; George and Terracol, 1997).…”

Clk post-transcriptional control denoises circadian transcription both temporally and spatially

“…The CLK-CYC heterodimer also activates the expression of VRILLE (VRI) and PAR-DOMAIN-PROTEIN 1 (PDP1), which have been postulated to be responsible for the oscillation of Clk mRNA 11,12 . Although the role of VRI in repressing Clk transcription is well established, recent reports suggest that PDP1 might not directly regulate Clk 13 . In addition to transcriptional control, post-transcriptional and post-translational regulations play also a central role in circadian timekeeping (for reviews see refs [14][15][16].…”