BIOLUMINESCENCE, namely the ability to emit light, has originated and evolved independently many times in many different organisms; the different systems are thus biochemically distinct and have many diverse functions. My research is concerned with the fundamental biochemical mechanisms whereby chemical energy in such systems is converted to light energy, the biological functions of bioluminescence, and the genetic control of the synthesis and expression of such systems. Studies with luminous bacteria led to the discovery of "autoinduction", now referred to as "quorum sensing" and shown to be functionally important in a wide number of bacterial groups. Studies with coelenterate bioluminescence led to the first discovery of an accessory emitter in bioluminescence, green fluorescent protein (GFP). The current research of my laboratory is concerned with the structure and organization of genes associated with both dipteran and dinoflagellate luminescence systems, as well as the structures of the luciferins and mechanisms of the luciferase enzymes responsible for catalyzing the reactions.
CIRCADIAN (daily) CONTROL represents a very fundamental yet still very poorly understood feature of higher organisms. Jet lag is a symptom of the disruption of our circadian system. Indeed, most organisms--and even individual unicells and some bacteria--possess a temporal control mechanism over many biochemical and physiological processes. Our research is concerned with the basic molecular and cellular mechanisms responsible for these rhythms in the bioluminescent dinoflagellate Gonyaulax polyedra. Earlier studies included the first demonstration of the phase-dependency of shifting of the clock by light and its action spectrum, as well as the unique ability of inhibitors of protein synthesis to cause such phase-shifts. The circadian rhythm of bioluminescence involves a daily synthesis and destruction of two proteins involved in the biochemical reaction. While the amounts of these proteins increase and decrease by a factor of 10 on a daily basis, the mRNAs for these proteins remain at the same level day and night. Synthesis is thus controlled at the translational level, a feature so far unique to this system. Current studies are focused on the role of protein phosphorylation in the cycle, the circadian regulation of gene expression, and the identity of such clock-controlled genes, as determined by microarray.