Most organisms possess an endogenous clock (circadian clock) that operates to control the time of the day at which various biological processes occur. In humans, circadian rhythms are manifested in various ways including work-rest cycles and drug tolerance and effectiveness. Malfunctions of the human clock are associated with several forms of psychiatric disorders including common forms of manic depression. Despite extensive research, the cellular and molecular basis of the biological clock are largely unknown. Therefore, the long term goal of clock research is to define the genetic and biochemical components of the clock and understand how the clock works. The filamentous fungus Neurospora crassa is one of the only two systems in which bona fide clock components have been identified. Extensive studies of the central clock component, frequency (frq), have already provided us with some very important information about the clock in general. The focus of this proposal is to study how frq is regulated at the temperature changes. The questions will be addressed in this proposal are: (1) what is the biological distinctions between the two FRQ forms and what is the molecular mechanism to achieve the temperature controlled translation? (2) How does temperature entrains Neurospora clock by changing the levels of frq mRNA and FRQ protein?
