A new clock gene

Researchers from three different labs have identified a new circadian gene in the mouse, according to two papers in Science and one paper in Cell published online this week. Mutagenesis screens revealed that mutations in a protein called FBXL3 lengthen the mouse circadian period by several hours, and biochemical analyses showed that FBXL3 is necessary for degradation of key circadian clock proteins. "I think this is a tremendously exciting discovery," said Steve Kay of the Scripps Research Institute in La Jolla, Calif., who was not involved in any of the work. "It shows that forward genetics is still a very powerful tool in identifying new clock genes."Mammalian circadian rhythms are generated by feedback loops of gene transcription and translation. The transcription factors CLOCK and BMAL1 drive expression of clock genes Period (Per) and Cryptochrome (Cry), whose proteins interact with CLOCK and BMAL1 to inhibit their own transcription. When PER...