There may be more driving circadian rhythms -- the daily cycles that mediate countless behavioral and physiological processes in living organisms -- than cyclical gene expression, as previously believed. A biochemical pathway in green algae and human red blood cells appears to maintain its own 24-hour cycle without the guidance of transcription, according to two studies published online today (January 26) in Nature.
Image: Wikimedia commons, Luis Miguel Bugallo Sánchez
"The findings are interesting and provocative," molecular biologist linkurl:Isaac Edery; of Rutgers University, who did not participate in the study, told The Scientist in an email. "What they show is that it is possible to drive a circadian rhythm in a molecular event in the absence of cyclical transcription or even transcription itself."Over the years, research in a variety of organisms has hinted at the existence of posttranscriptional clock regulators, but the molecular details remained undiscovered. Then, in 2005,...
Ostreococcus tauriNatureJ.S. O'Neill and A.B. Reddy, "Circadian clocks in human red blood cells," Nature, 469:498-503, 2011.J.S. O'Neill, et al., "Circadian rhythms persist without transcription," Nature, 469:554-8, 2011.

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