Related Experiment Video
Updated: May 13, 2026
06:13
Solid Plate-based Dietary Restriction in Caenorhabditis elegans
Published on: May 28, 2011
Circadian rhythms persist without transcription in a eukaryote
John S O'Neill1, Gerben van Ooijen, Laura E Dixon
1Centre for Systems Biology at Edinburgh, C.H. Waddington Building, Mayfield Road, Edinburgh EH9 3JD, UK.
Nature
|January 29, 2011
Summary
Daily rhythms in eukaryotes are not solely driven by gene expression. Non-transcriptional mechanisms, like peroxiredoxin oxidation, are sufficient for circadian timekeeping and conserved across species.
Area of Science:
- * Chronobiology and molecular biology.
- * Eukaryotic circadian systems.
Background:
- * Circadian rhythms regulate daily biological processes in eukaryotes, driven by transcriptional-translational feedback loops.
- * While transcriptional clock components vary across kingdoms, post-transcriptional mechanisms are increasingly recognized.
- * The unicellular alga *Ostreococcus tauri* has a simplified clock with plant-like features.
Purpose of the Study:
- * To investigate the sufficiency and conservation of non-transcriptional mechanisms in eukaryotic circadian timekeeping.
- * To re-evaluate the role of transcriptional components in oscillator function in light of post-translational findings.
Main Methods:
- * Analysis of circadian rhythms in *Ostreococcus tauri*.
- * Identification of transcription-independent rhythmic biomarkers.
- * Pharmacological modulation of mammalian clock mechanisms and assessment of effects on *Ostreococcus* rhythms.
Main Results:
- * Non-transcriptional mechanisms are sufficient to maintain circadian timekeeping in eukaryotes, often working alongside transcriptional elements.
- * Oxidation of peroxiredoxin proteins identified as a transcription-independent rhythmic biomarker, also observed in mammals.
- * Pharmacological agents affecting mammalian circadian rhythms impact *Ostreococcus*.
Conclusions:
- * Post-translational mechanisms and specific rhythmic markers (e.g., peroxiredoxin oxidation) are more conserved across eukaryotic kingdoms than transcriptional clock regulators.
- * Suggests that ancient circadian oscillator components may be non-transcriptional, similar to cyanobacteria, and conserved throughout evolution.
Related Concept Videos
01:29Non-nuclear Inheritance
Most DNA resides in the nucleus of a cell. However, some organelles in the cell cytoplasm—such as chloroplasts and mitochondria—also have their own DNA. These organelles replicate their DNA independently of the nuclear DNA of the cell in which they reside. Non-nuclear inheritance describes the inheritance of genes from structures other than the nucleus.
01:29Non-nuclear Inheritance
Most DNA resides in the nucleus of a cell. However, some organelles in the cell cytoplasm—such as chloroplasts and mitochondria—also have their own DNA. These organelles replicate their DNA independently of the nuclear DNA of the cell in which they reside. Non-nuclear inheritance describes the inheritance of genes from structures other than the nucleus.
02:51Multi-species Conserved Sequences
Next-generation sequencing technologies have created large genomic databases of a variety of animals and plants. Ever since the human genome project was completed, scientists studied the genome of primates, mammals, and other phylogenetically distant living beings. Such large-scale studies have provided new insights into the evolutionary relationship between organisms.
Although the genome of each species varies greatly from each other, a few sequences are highly conserved. Such conserved DNA...
Although the genome of each species varies greatly from each other, a few sequences are highly conserved. Such conserved DNA...
02:38S-Cdk Initiates DNA Replication
The cell cycle is a series of events leading to DNA duplication followed by the division of cell content to form two daughter cells. The cell cycle progresses in four stages—the cell increases in size (gap 1 or G1-phase), duplicates its DNA (synthesis or S-phase), prepares to divide (gap 2 or G2-phase), and divides (mitosis or M-phase).
Two states at the origin of replication
In eukaryotes, the initiation of replication occurs at many sites on the chromosomes, called the origins of replication.
Two states at the origin of replication
In eukaryotes, the initiation of replication occurs at many sites on the chromosomes, called the origins of replication.
02:38S-Cdk Initiates DNA Replication
The cell cycle is a series of events leading to DNA duplication followed by the division of cell content to form two daughter cells. The cell cycle progresses in four stages—the cell increases in size (gap 1 or G1-phase), duplicates its DNA (synthesis or S-phase), prepares to divide (gap 2 or G2-phase), and divides (mitosis or M-phase).
Two states at the origin of replication
In eukaryotes, the initiation of replication occurs at many sites on the chromosomes, called the origins of replication.
Two states at the origin of replication
In eukaryotes, the initiation of replication occurs at many sites on the chromosomes, called the origins of replication.
01:23Red Algae
Red algae, also known as rhodophytes, are primarily found in marine environments, though some species inhabit freshwater and terrestrial ecosystems. These organisms exist in both unicellular and multicellular forms, with some multicellular varieties reaching macroscopic sizes.As phototrophic organisms, red algae contain chlorophyll a; however, their chloroplasts lack chlorophyll b. Instead, they possess phycobiliproteins, which serve as major light-harvesting pigments, similar to those found in...