title: Circadian clocks: a tale of two feedback loops.
abstract: Circadian clocks in a wide range of organisms are thought to consist of two interdependent transcriptional feedback loops. In Drosophila, the first loop has been well characterized and controls rhythmic period expression. In this issue of Cell, define a role for a transcriptional activator and a repressor in the second feedback loop.
authors.affiliation: Department of Neurobiology and Physiology, Northwestern University, Evanston, IL 60208, USA.
authors.forename: Ravi
authors.initials: R
authors.lastname: Allada
mesh_terms: D000818:Animals; D001683:Biological Clocks / Q000235:genetics*; D056926:CLOCK Proteins; D002940:Circadian Rhythm / Q000235:genetics*; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000235:genetics* / Q000378:metabolism; D005246:Feedback / Q000502:physiology*; D005786:Gene Expression Regulation / Q000235:genetics; D008954:Models, Biological; D014157:Transcription Factors / Q000235:genetics; D015533:Transcriptional Activation / Q000235:genetics
chemical_list: C120526:Clk protein, Drosophila; D029721:Drosophila Proteins; D014157:Transcription Factors; D056926:CLOCK Proteins