Dr. Liu’s research at UT Southwestern involves the study of circadian clocks, which have been described in almost all organisms ranging in complexity from single cells to mammals, and function to control daily rhythms in a variety of biochemical, cellular, physiological and behavioral events. These rhythms have a period close to 24 hours (circadian) and persist in the absence of external time cues. In humans and other mammals, circadian clocks control events such as sleep-wake and activity cycles, body temperature cycles, endocrine functions, and gene expression. The influence of a functional clock on human temporal regulation is evident by the jet lag felt by long distance travelers. Dr. Liu’s lab is using filamentous fungus Neurospora crassa, one of the best-studied model organisms for circadian clocks, to understand the molecular mechanisms of the circadian clock. In Neurospora, the circadian clock acts to control a variety of processes, and previous studies have shown that the Neurospora circadian clock is an auto-regulated negative feedback loop in which the frequency (frq) gene is an important component. Dr. Liu’s lab is using molecular, biochemical and physiological approaches to answer three general questions: (1) what are the components of the input pathways to the clock and how do environmental signals entrain the clock; (2) what are the genes that make up the oscillator and how are they regulated to generate rhythms; and (3) how does the clock control rhythmic output events?
