Circadian rhythms identified in Caenorhabditis elegans by in vivo long-term monitoring of a bioluminescent reporter

Abstract

Circadian rhythms are based on endogenous clocks that allow organisms to adjust their physiology and behavior by entrainment to the solar day and, in turn, to select the optimal times for most biological variables. Diverse model systems-including mice, flies, fungi, plants, and bacteria-have provided important insights into the mechanisms of circadian rhythmicity. However, the general principles that govern the circadian clock of Caenorhabditis elegans have remained largely elusive. Here we report robust molecular circadian rhythms in C. elegans recorded with a bioluminescence assay in vivo and demonstrate the main features of the circadian system of the nematode. By constructing a luciferase-based reporter coupled to the promoter of the suppressor of activated let-60 Ras (sur-5) gene, we show in both population and single-nematode assays that C. elegans expresses ∼24-h rhythms that can be entrained by light/dark and temperature cycles. We provide evidence that these rhythms are temperature-compensated and can be re-entrained after phase changes of the synchronizing agents.In addition, we demonstrate that light and temperature sensing requires the photoreceptors LITE and GUR-3, and the cyclic nucleotidegated channel subunit TAX-2. Our results shed light on C. elegans circadian biology and demonstrate evolutionarily conserved features in the circadian system of the nematode.C. elegans | circadian rhythms | luminescence | temperature | light

Identification of circadian rhythms inNannochloropsisspecies using bioluminescence reporter lines

“…Casein kinase 1 (CK1) is a conserved component of circadian systems in eukaryotes and the pharmacological inhibition of CK1 affects the circadian period in mammals (Badura et al , 2007, Eide et al , 2005, Walton et al , 2009), Drosophila melanogaster (Meng et al , 2010), Neurospora crassa (Querfurth et al , 2011), Ostreococcus tauri (van Ooijen et al , 2013) and Caenorhabditis elegans (Goya et al , 2016). N. oceanica contains a CK1 gene with 72% identity with mouse casein kinase 1 ε (NannoCCMP1779|10930); this gene cycles under light/dark conditions with a peak at dawn (Figure S13a).…”

Caenorhabditis elegans and its applicability to studies on restless legs syndrome

“…The study also demonstrated that light and temperature detection involve the use of photoreceptors GUR-3 and LITE, as well as TAX-2 cyclic nucleotide-gated channel subunit. Importantly, this bioluminescence assay is extremely sensitive, non-invasive and has immediate resolution (Goya et al, 2016). Therefore, C. elegans can be optimized to elucidate the molecular mechanisms behind the circadian patterns of RLS symptoms using those characterized behavioural and physiological activities controlled by circadian rhythms in C. elegans .…”

Identification of circadian rhythms in Nannochloropsis species using bioluminescence reporter lines

“…Casein kinase 1 (CK1) is a conserved component of circadian systems in eukaryotes and the pharmacological inhibition of CK1 affects the circadian period in mammals (Eide et al, 2005;Badura et al, 2007;Walton et al, 2009), Drosophila melanogaster (Meng et al, 2010), Neurospora crassa (Querfurth et al, 2011), Ostreococcus tauri (van Ooijen et al, 2013) and Caenorhabditis elegans (Goya et al, 2016). Nannochloropsis oceanica contains a CK1 gene with 72% identity with mouse casein kinase 1 e (Nan-noCCMP1779|10930); this gene cycles under light/dark conditions with a peak at dawn ( Figure S13a).…”