Conditional rescue of the learning deficit of leonardo mutants. E.M. Skoulakis , N. Philip. Department of Biology, cAIMS and Faculty of Neuroscience. Texas A&M University. College Station TX 77843.

   The 14-3-3 proteins are small acidic cytosolic proteins abundant in the nervous system with putative functions in regulation of exocytosis, and activity modulation of the kinases PKC, Raf and Bcr. Viable lesions in the D14-3-3 z gene leonardo that decrease the level of the protein in the mushroom bodies precipitate deficits in negatively reinforced olfactory learning. Since the gene is essential, to unequivocally establish that the learning deficits are not due to undetectable developmental abnormalities, we rescued the homozygous lethality associated with three independent transposon insertions in the gene by conditional expression of leo cDNAs. These rescued homozygotes exhibit learning deficiencies identical to these of previously characterized mutants. Moreover, conditional expression of the transgenes fully rescues the learning deficit in either rescued lethal homozygotes, or viable tissue specific mutants. The results strongly support acute role(s) for LEONARDO in learning processes in adults.