Investigating the Molecular Basis of Courtship Conditioning in Drosophila melanogaster: A role for cuticular hydrocarbons and CREB

The two experiments presented here investigate possible molecular mechanisms in the formation of courtship conditioning memory in D. melanogaster through genetic manipulations using the Gal4 UAS gene expression system. First, the hypothesis that a chemical cue on the female cuticle acts as the conditioned stimulus (CS) in courtship conditioning was tested by manipulating the cuticular hydrocarbon profile of test target flies. We demonstrate that hydrocarbon manipulation is sufficient to determine the subject\u27s demonstration of a learned response. Specifically, the hydrocarbons cis 7-pentacosene and cis cis 7,1l-nonacosadiene appear to be candidates for the CS. The second experiment addressed a possible role of the transcription factor CREB in mushroom bodies (MBs) by testing flies with overexpressed wild- type dCREB2-a and dCREB2-b in the MBs (through Gal4 control of the 30y driver) in the short-term courtship conditioning paradigm. Lack of normal memory in the dCREB2-a control genotypes prevented further analysis of these results. dCREB2-b overexpression appeared to cause a short-term memory deficit. This is not consistent with previous studies of the time-course of CREB induction in learning and memory, suggesting a possible developmental effect of chronic dCREB2-b overexpression driven by 30y