Biomedical subjects

Adrian W Moore

Publications and source records attributed to Adrian W Moore.

4 recordsLinked to original sources

PubMed2005

Nerfin-1 is required for early axon guidance decisions in the developing Drosophila CNS.

Many studies have focused on the mechanisms of axon guidance; however, little is known about the transcriptional control of the navigational components that carryout these decisions. This report describes the functional analysis of Nerfin-1, a nuclear regulator of axon guidance required for a subset of early pathfinding events in the developing Drosophila CNS. Nerfin-1 belongs to a highly conserved subfamily of Zn-finger proteins with cognates identified in nematodes and man. We show that the neural precursor gene prospero is essential for nerfin-1 expression. Unlike nerfin-1 mRNA, which is expressed in many neural precursor cells, the encoded Nerfin-1 protein is only detected in the nuclei of neuronal precursors that will divide just once and then transiently in their nascent neurons. Although nerfin-1 null embryos have no discernible alterations in neural lineage development nor in neuronal or glial identities, CNS pioneering neurons require nerfin-1 function for early axon guidance decisions. Furthermore, nerfin-1 is required for the proper development of commissural and connective axon fascicles. Our studies also show that Nerfin-1 is essential for the proper expression of robo2, wnt5, derailed, G-oalpha47A, Lar, and futsch, genes whose encoded proteins participate in these early navigational events.

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PubMed2004

Conversion of neurons and glia to external-cell fates in the external sensory organs of Drosophila hamlet mutants by a cousin-cousin cell-type respecification.

The Drosophila external sensory organ forms in a lineage elaborating from a single precursor cell via a stereotypical series of asymmetric divisions. HAMLET transcription factor expression demarcates the lineage branch that generates two internal cell types, the external sensory neuron and thecogen. In HAMLET mutant organs, these internal cells are converted to external cells via an unprecedented cousin-cousin cell-fate respecification event. Conversely, ectopic HAMLET expression in the external cell branch leads to internal cell production. The fate-determining signals NOTCH and PAX2 act at multiple stages of lineage elaboration and HAMLET acts to modulate their activity in a branch-specific manner.

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PubMed2003

Dendrites of distinct classes of Drosophila sensory neurons show different capacities for homotypic repulsion.

BACKGROUND: Understanding how dendrites establish their territory is central to elucidating how neuronal circuits are built. Signaling between dendrites is thought to be important for defining their territories; however, the strategies by which different types of dendrites communicate are poorly understood. We have shown previously that two classes of Drosophila peripheral da sensory neurons, the class III and class IV neurons, provide complete and independent tiling of the body wall. By contrast, dendrites of class I and class II neurons do not completely tile the body wall, but they nevertheless occupy nonoverlapping territories. RESULTS: By developing reagents to permit high-resolution studies of dendritic tiling in living animals, we demonstrate that isoneuronal and heteroneuronal class IV dendrites engage in persistent repulsive interactions. In contrast to the extensive dendritic exclusion shown by class IV neurons, duplicated class III neurons showed repulsion only at their dendritic terminals. Supernumerary class I and class II neurons innervated completely overlapping regions of the body wall, and this finding suggests a lack of like-repels-like behavior. CONCLUSIONS: These data suggest that repulsive interactions operate between morphologically alike dendritic arbors in Drosophila. Further, Drosophila da sensory neurons appear to exhibit at least three different types of class-specific dendrite-dendrite interactions: persistent repulsion by all branches, repulsion only by terminal dendrites, and no repulsion.

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PubMed2002

hamlet, a binary genetic switch between single- and multiple- dendrite neuron morphology.

The dendritic morphology of neurons determines the number and type of inputs they receive. In the Drosophila peripheral nervous system (PNS), the external sensory (ES) neurons have a single nonbranched dendrite, whereas the lineally related multidendritic (MD) neurons have extensively branched dendritic arbors. We report that hamlet is a binary genetic switch between these contrasting morphological types. In hamlet mutants, ES neurons are converted to an MD fate, whereas ectopic hamlet expression in MD precursors results in transformation of MD neurons into ES neurons. Moreover, hamlet expression induced in MD neurons undergoing dendrite outgrowth drastically reduces arbor branching.

Amino Acid Sequence↗