The gene machine: Controlling the creation of synapse formation l. copeland-hardin Howard University P.i. & Mentor: Tory Herman A properly functioning nervous system allows an organism to perform everyday activities. Neurons are major components of the nervous system. Synapses are the connections between neurons. Presynaptic Postsynaptic Axon Dendrite The connections between neurons and synapses are very specific. Jump starting a car What genes participate in forming the correct synapse connections between neurons? We studied the R7 photoreceptor neurons of Drosophila. R7s Normal R7 neurons form synapses in the M6 layer of the medulla. Medulla Retina M6 layer Goal: remove each of the 14,000 fly genes from R7s and see if they form synapses. We looked at mosaic animals in which only R7s are missing genes. Recombination does not normally happen during mitosis. We used FLP-recombinase to induce mitotic recombination in R7 parent cells. DEFICIENCY FRT 40 FLP Recombinas e Throughout the summer I I set up 78 genetic crosses. I dissected 6-10 brains from the progeny of 67 of the crosses. So far we have analyzed 18 genotypes of flies under the confocal microscope. 17 of the deficiencies did not affect synapse formation. Deficiency 7823 synapses are abnormal. Wild type Deficiency7823 synapses look like syd-1 mutant synapses. Mutant syd-1 A16ACXAACXBACXCACXECG CG CG CG5075CG5122CG5142CG5204CG9928CG9932 CG9934DnaJ-HPk34ASir2 Tor Vha68- 1 Vha68- 2 Df7823 removes 21 genes. We found a new gene responsible for forming synapses. Future Directions DETERMINE WHICH GENE(S) OF DEFICIENCY 7823 ARE RESPONSIBLE FOR MUTATED SYNAPSES FINISH SCANNING OF OTHER DEFICIENCIES Acknowledgment s MARCM and Gal8 0 make the homozygous mutant R7s green. DEFICIENCY FRT 40 FLP Recombinas e Gal80