People / Graduate Students

Joowon Suh

Drosophila Ebony, which corresponds to N-b-alanyl-biogenic amine synthetase (BAS), is required for circadian locomotor activity rhythms. Ebony mutant fly exhibits arrhythmic circadian rhythmic behavior. My research project is about characterizing the function of ebony gene to regulate circadian behavior using molecular, cellular, and genetic tools.  Although studies of mammals and insects suggest that glia may be required for normal circadian rhythmicity, specific glial factors that are required for circadian behavior have not been identified in either system. I showed that surprisingly, ebony is exclusively expressed in glial cells of the brain by immunocytochemistry and expression of a wild-type ebony+ transgene in glial cells is sufficient for rescue of mutant circadian behavior. Rhythms in per/tim RNA or protein abundance and in PDF peptide immunostaining are normal in ebony mutants, which indicates that ebony acts downstream of the molecular clock. Our genetic evidence show that Ebony functions in dopaminergic signaling. Our studies thus suggest a model for ebony function wherein Ebony glia participate in the clock control of dopaminergic function and the orchestration of circadian activity rhythms. Further studies are being performed to elucidate more detailed role of glia and dopamine on the regulation of circadian rhythmic behavior.