Department of Neurobiology; Tzumin Lee Lab; Graduate School of Biomedical Sciences, Neuroscience Program
Aging; Animals; Axons; Biological Markers; Drosophila Proteins; Drosophila melanogaster; Gene Knockdown Techniques; Gene Silencing; MicroRNAs; Morphogenesis; Mushroom Bodies; Phenotype; Receptors, Cytoplasmic and Nuclear
Neuroscience and Neurobiology
Nuclear receptors (NRs) comprise a family of ligand-regulated transcription factors that control diverse critical biological processes including various aspects of brain development. Eighteen NR genes exist in the Drosophila genome. To explore their roles in brain development, we knocked down individual NRs through the development of the mushroom bodies (MBs) by targeted RNAi. Besides recapitulating the known MB phenotypes for three NRs, we found that unfulfilled (unf), an ortholog of human photoreceptor specific nuclear receptor (PNR), regulates axonal morphogenesis and neuronal subtype identity. The adult MBs develop through remodeling of gamma neurons plus de-novo elaboration of both alpha'/beta' and alpha/beta neurons. Notably, unf is largely dispensable for the initial elaboration of gamma neurons, but plays an essential role in their re-extension of axons after pruning during early metamorphosis. The subsequently derived MB neuron types also require unf for extension of axons beyond the terminus of the pruned bundle. Tracing single axons revealed misrouting rather than simple truncation. Further, silencing unf in single-cell clones elicited misguidance of axons in otherwise unperturbed MBs. Such axon guidance defects may occur as MB neurons partially lose their subtype identity, as evidenced by suppression of various MB subtype markers in unf knockdown MBs. In sum, unf governs axonal morphogenesis of multiple MB neuron types, possibly through regulating neuronal subtype identity.
Rights and Permissions
Copyright: © 2009 Lin et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
DOI of Published Version
Lin S, Huang Y, Lee T (2009) Nuclear Receptor Unfulfilled Regulates Axonal Guidance and Cell Identity of Drosophila Mushroom Body Neurons. PLoS ONE 4(12): e8392. doi:10.1371/journal.pone.0008392. Link to article on publisher's site
Lin, Suewei; Huang, Yaling; and Lee, Tzumin, "Nuclear receptor unfulfilled regulates axonal guidance and cell identity of Drosophila mushroom body neurons" (2009). Open Access Articles. 2197.