Isoforms of terminal selector Mamo control axon guidance during adult Drosophila memory center construction via Semaphorin-1a.

In animals undergoing metamorphosis, the appearance of the nervous system is coincidently transformed by the morphogenesis of neurons. Such morphogenic alterations are exemplified in three types of intrinsic neurons in the Drosophila memory center. In contrast to the well-characterized remodeling of γ neurons, the morphogenesis of α/β and α'/β' neurons has not been adequately explored.

Hormone-controlled changes in the differentiation state of post-mitotic neurons.

While we think of neurons as having a fixed identity, many show spectacular plasticity. Metamorphosis drives massive changes in the fly brain; neurons that persist into adulthood often change in response to the steroid hormone ecdysone. Besides driving remodeling, ecdysone signaling can also alter the differentiation status of neurons.

Drosophila septin interacting protein 1 regulates neurogenesis in the early developing larval brain.

Neurogenesis in the Drosophila central brain progresses dynamically in order to generate appropriate numbers of neurons during different stages of development. Thus, a central challenge in neurobiology is to reveal the molecular and genetic mechanisms of neurogenesis timing. Here, we found that neurogenesis is significantly impaired when a novel mutation, Nuwa, is induced at early but not late larval stages.

Visualization of Endogenous Type I TGF-β Receptor Baboon in the Drosophila Brain.

The transforming growth factor β (TGF-β) signaling pathway is evolutionarily conserved and widely used in the animal kingdom to regulate diverse developmental processes. Prior studies have shown that Baboon (Babo), a Drosophila type I TGF-β receptor, plays essential roles in brain development and neural circuit formation. However, the expression pattern for Babo in the developing brain has not been previously reported.

FOXO regulates cell fate specification of Drosophila ventral olfactory projection neurons.

Diverse types of neurons must be specified in the developing brain to form the functional neural circuits that are necessary for the execution of daily tasks. Here, we describe the participation of Forkhead box class O (FOXO) in cell fate specification of a small subset of Drosophila ventral olfactory projection neurons (vPNs). Using the two-color labeling system, twin-spot MARCM, we determined the temporal birth order of each vPN type, and this characterization served as a foundation to investigate regulators of cell fate specification.

Semaphorin-1a prevents Drosophila olfactory projection neuron dendrites from mis-targeting into select antennal lobe regions.

Elucidating how appropriate neurite patterns are generated in neurons of the olfactory system is crucial for comprehending the construction of the olfactory map. In the Drosophila olfactory system, projection neurons (PNs), primarily derived from four neural stem cells (called neuroblasts), populate their cell bodies surrounding to and distribute their dendrites in distinct but overlapping patterns within the primary olfactory center of the brain, the antennal lobe (AL). However, it remains unclear whether the same molecular mechanisms are employed to generate the appropriate dendritic patterns in discrete AL glomeruli among PNs produced from different neuroblasts.

Drosophila microRNA-34 Impairs Axon Pruning of Mushroom Body γ Neurons by Downregulating the Expression of Ecdysone Receptor.

MicroRNA-34 (miR-34) is crucial for preventing chronic large-scale neurite degeneration in the aged brain of Drosophila melanogaster. Here we investigated the role of miR-34 in two other types of large-scale axon degeneration in Drosophila: axotomy-induced axon degeneration in olfactory sensory neurons (OSNs) and developmentally related axon pruning in mushroom body (MB) neurons. Ectopically overexpressed miR-34 did not inhibit axon degeneration in OSNs following axotomy, whereas ectopically overexpressed miR-34 in differentiated MB neurons impaired γ axon pruning.

Morphogenetic Studies of the Drosophila DA1 Ventral Olfactory Projection Neuron.

In the Drosophila olfactory system, odorant information is sensed by olfactory sensory neurons and relayed from the primary olfactory center, the antennal lobe (AL), to higher olfactory centers via olfactory projection neurons (PNs). A major portion of the AL is constituted with dendrites of four groups of PNs, anterodorsal PNs (adPNs), lateral PNs (lPNs), lateroventral PNs (lvPNs) and ventral PNs (vPNs). Previous studies have been focused on the development and function of adPNs and lPNs, while the investigation on those of lvPNs and vPNs received less attention.