@article {786,
	title = {Development of the Drosophila mushroom bodies: sequential generation of three distinct types of neurons from a neuroblast.},
	journal = {Development},
	volume = {126},
	year = {1999},
	month = {1999 Sep},
	pages = {4065-76},
	abstract = {<p>The mushroom bodies (MBs) are prominent structures in the Drosophila brain that are essential for olfactory learning and memory. Characterization of the development and projection patterns of individual MB neurons will be important for elucidating their functions. Using mosaic analysis with a repressible cell marker (Lee, T. and Luo, L. (1999) Neuron 22, 451-461), we have positively marked the axons and dendrites of multicellular and single-cell mushroom body clones at specific developmental stages. Systematic clonal analysis demonstrates that a single mushroom body neuroblast sequentially generates at least three types of morphologically distinct neurons. Neurons projecting into the (gamma) lobe of the adult MB are born first, prior to the mid-3rd instar larval stage. Neurons projecting into the alpha{\textquoteright} and beta{\textquoteright} lobes are born between the mid-3rd instar larval stage and puparium formation. Finally, neurons projecting into the alpha and beta lobes are born after puparium formation. Visualization of individual MB neurons has also revealed how different neurons acquire their characteristic axon projections. During the larval stage, axons of all MB neurons bifurcate into both the dorsal and medial lobes. Shortly after puparium formation, larval MB neurons are selectively pruned according to birthdays. Degeneration of axon branches makes early-born gamma neurons retain only their main processes in the peduncle, which then project into the adult gamma lobe without bifurcation. In contrast, the basic axon projections of the later-born (alpha{\textquoteright}/beta{\textquoteright}) larval neurons are preserved during metamorphosis. This study illustrates the cellular organization of mushroom bodies and the development of different MB neurons at the single cell level. It allows for future studies on the molecular mechanisms of mushroom body development.</p>
},
	keywords = {Animals, Axons, Biological, Brain, Cell Differentiation, Clone Cells, Drosophila melanogaster, Genetic, Genetic Markers, Genetic Techniques, Genetically Modified, Larva, Metamorphosis, Mitosis, Neurons, Olfactory Pathways, Recombination},
	issn = {0950-1991},
	author = {Lee, T and Lee, A and Luo, L}
}
@article {785,
	title = {Mosaic analysis with a repressible cell marker for studies of gene function in neuronal morphogenesis.},
	journal = {Neuron},
	volume = {22},
	year = {1999},
	month = {1999 Mar},
	pages = {451-61},
	abstract = {<p>We describe a genetic mosaic system in Drosophila, in which a dominant repressor of a cell marker is placed in trans to a mutant gene of interest. Mitotic recombination events between homologous chromosomes generate homozygous mutant cells, which are exclusively labeled due to loss of the repressor. Using this system, we are able to visualize axonal projections and dendritic elaboration in large neuroblast clones and single neuron clones with a membrane-targeted GFP marker. This new method allows for the study of gene functions in neuroblast proliferation, axon guidance, and dendritic elaboration in the complex central nervous system. As an example, we show that the short stop gene is required in mushroom body neurons for the extension and guidance of their axons.</p>
},
	keywords = {Animals, Axons, Central Nervous System, Chromosomes, Drosophila, Genetic Markers, Mitosis, Morphogenesis, Mosaicism, Mutation, Neurons, Repressor Proteins, Transgenes},
	issn = {0896-6273},
	author = {Lee, T and Luo, L}
}
