How do SCN neurons measure out 24 hours? Work on the circadian clocks of species ranging from bacteria to fungi to fruit flies has revealed a common thread, that the molecular basis for circadian rhythmicity is the rhythmic synthesis of "clock" molecules. In each of these species, and in mammals, molecules are synthesized rhythmically, and these molecules then feed back to turn off their own synthesis. This forms what is called a "transcriptional-translational feedback loop." Mutations of specific genes within the feedback loop result in altered or disrupted rhythmicity. Recently, great advances have been made in identifying the components of the circadian feedback loop in mammals, and in defining the specific roles of individual gene products in the circadian clock (reviewed in Reppert & Weaver 2002). The aim of this research is to understand the molecular mechanisms underlying generation and entrainment of circadian rhythms in mammals.

Current Research Projects:

We are studying behavioral and molecular phenotypes of mice with genetic defects altering circadian behavior.  We continue to generate line of mice with targeted disruption of genes relevant to circadian rhythms.  Other areas of interest are to identify the effects of clock gene mutations on other behavioral and physiological processes, including sleep, and to understand the importance of local oscillators in tissues outside the brain. 

Please use the Publications Tab at the top of this page for the most up-to-date description of this research program and my collaborators.