Abstract
The circadian researches in Drosophila melanogaster indicated that the fly pacemaker cells are 8 cells located on ventral bilateral of the brain called “lateral neurons” (LNvs). The expression patterns of these 8 cells innervate both optic lobes and central brain, and release a kind of neuropeptide called pigment-dispersing factor (PDF) served as behavior circadian. In my study, since many transgenic flies were produced recent years， I was able to express different reporters on these LNvs by UAS/GAL4 system and to study further the development and circuit of these LNvs. Flip-out let us known the expression pattern of single LNvs. Combing mCD8-GFP and nuclear localized GFP let us to know the pdf expression pattern and cell number during different developmental stages. In the study of the axonal and dendritic distribution of these LNvs, unlike previous guesses, I found that several posterior optic tracts (POT) originated from l-LNvs and fibers send to central brain from s-LNvs are dendrites. In addition, I also found Acetylcholine and octopamine are not the neurotransmitters used in LNvs. Finally, I used a UV sensitive fly “UAS-kaede” constructed by our lab to prove that the cell lineage between 3 instar larvae and adults. In aspect of cell birth, I think it is difficult to solve these questions entirely because the metabolic rate of LNvs is very fast. However, kaede do provide us a new direction and a new insight to study the development of these LNvs. In the future, we may combine more image techniques, like MARCM, to unravel the mystery of these clock neurons entirely.