Etude génétique de connectivité neuronale chez Drosophila melanogaster :le cas du gène POXN

Doctorat en Sciencesinfo:eu-repo/semantics/nonPublishe

The leg of Drosophila as a model system for the analysis of neuronal diversity

The neurons innervating insect sense organs vary in number, shape, dendritic morphology, axonal projections and connectivity, providing abundant material for the genetic analysis of neuronal diversity. Here we describe the leg of Drosophila as a potential model system for this analysis. The leg of Drosophila comprises a variety of sense organs arranged in a precise ard reproducible pattern. The cell bodies of the sensory neurons are located near the organ they innervate, which greatly facilitates their identification and accessibility. The development of the leg from its progenitor structure, the imaginal disc, is known in good detail. In particular, the time of appearance and of divisions of the sense organ precursors is known. The origin and mode of formation of the leg nerve (through which all sensory axons project into the central nervous system) has been described. The central projections of some of the sensory neurons have been examined by horse-radish peroxidase backfill or DiI labelling. Finally, the expression of several genes that control the differentiation of various types of sensory neurons can be manipulated at will. We illustrate these different aspects, and discuss the potentials and shortcomings of this system.SCOPUS: cp.jinfo:eu-repo/semantics/publishe

The gene poxn controls different steps of the formation of chemosensory organs in drosophila

The gene poxn codes for a transcriptional regulator that specifies poly-innervated (chemosensory), as opposed to mono-innervated (mechanosensory), organs in Drosophila. The ectopic expression of poxn during metamorphosis results in a transformation of the morphology and central projection of adult mechanosensory organs toward those of chemosensory organs. Here we show, by electron microscopy analysis of normal and transformed bristles and by Dil labeling of the innervating neurons, that poxn also controls the number of neurons. To determine whether poxn can transform not only the sense organ precursor cells but also their daughter cells, we examine the effects of the ectopic expression of poxn at different stages of the lineage, and we conclude that poxn can act at a late stage to affect the fate of the undifferentiated neuron. © 1994.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Connectivity of chemosensory neurons is controlled by gene poxn in Drosophila

SCOPUS: ar.jinfo:eu-repo/semantics/publishe