New circadian timer?

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;http://lifesci.rutgers.edu/%7Emolbiosci/faculty/edery.html 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,...