Regulation of clock genes.

A recent explosion in the identification of new clock components in cyanobacteria, fungi, insects, mammals as well as potential candidates in plants has uncovered common themes among the structure, function and regulation of these components. Positive and negative interactions that are organized in negative feedback loops have been found crucial for clock function. Both transcriptional and posttranscriptional mechanisms appear to be important for circadian rhythm generation in all of these organisms.