Posts Tagged: neuro

pySolo: a complete suite for sleep analysis in Drosophila

Bioinformatics. 2009 Jun 1; 25: 1466-1467
pySolo: a complete suite for sleep analysis in Drosophila
Giorgio F. Gilestro, Chiara Cirelli

pySolo is a multi-platform software for analysis of sleep and locomotor activity in Drosophila melanogaster. pySolo provides a user-friendly graphic interface and it has been developed with the specific aim of being accessible, portable, fast and easily expandable through an intuitive plug-in structure. Support for development of additional plug-ins is provided through a community website.
Availability: Software and documentation are located at pySolo is a free software and the entire project is leased under the GNU General Public License.
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Redundant mechanisms for regulation of midline crossing in Drosophila

PLoS ONE. 2008;3(11):e3798. Epub 2008 Nov 24.
Redundant mechanisms for regulation of midline crossing in Drosophila.
Gilestro GF.

During development, all neurons have to decide on whether to cross the longitudinal midline to project on the contralateral side of the body. In vertebrates and invertebrates regulation of crossing is achieved by interfering with Robo signalling either through sorting and degradation of the receptor, in flies, or through silencing of its repulsive activity, in vertebrates. Here I show that in Drosophila a second mechanism of regulation exists that is independent of sorting. Using in vitro and in vivo assays, I mapped the region of Robo that is sufficient and required for its interaction with Comm, its sorting receptor. By modifying that region, I generated new forms of Robo that are insensitive to Comm sorting in vitro and in vivo, yet still able to normally translate repulsive activity in vivo. Using gene targeting by homologous recombination I created new conditional alleles of robo that are sorting defective (robo(SD)). Surprisingly, expression of these modified proteins results in phenotypically normal flies, unveiling a sorting independent mechanism of regulation.

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Regulation of commissural axon pathfinding by slit and its Robo receptors

Annu Rev Cell Dev Biol. 2006;22:651-75.
Regulation of commissural axon pathfinding by slit and its Robo receptors.
Barry J. Dickson, Giorgio F. Gilestro

Commissural axons grow along complex pathways toward, across, and beyond the midline of the central nervous system. Taking commissural axons in the vertebrate spinal cord and the Drosophila ventral nerve cord as examples, we examine how commissural axon pathfinding is regulated by the Slit family of guidance cues and their Robo family receptors. We extract several principles that seem likely to apply to other axons and other contexts, such as the reiterative use of the same guidance molecules in distinct pathfinding decisions, the transcriptional specification of a pathway, the posttranscriptional regulation of growth along the pathway, and the possible role of feedback mechanisms to ensure the fidelity of pathfinding choices. Such mechanisms may help explain how a relatively small number of guidance molecules can generate complex and stereotyped wiring patterns. We also highlight the many gaps in our understanding of commissural axon pathfinding and question some widely accepted views. We hope that this review encourages further efforts to tackle these questions, in the expectation that this system will continue to reveal the general principles of axon pathfinding.
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Plexin-B3 is a functional receptor for semaphorin 5A

EMBO Rep. 2004 Jul;5(7):710-4. Epub 2004 Jun 25.
Plexin-B3 is a functional receptor for semaphorin 5A
Artigiani S, Conrotto P, Fazzari P, Gilestro GF, Barberis D, Giordano S, Comoglio PM, Tamagnone L.

Semaphorins are a large family of molecular cues implicated in neural development and in a variety of functions outside the nervous system. Semaphorin 5A (Sema5A) is a transmembrane semaphorin, containing seven thrombospondin type-1 repeats, which was recently found to control axon guidance. Here we show that plexin-B3 is a high-affinity receptor specific for Sema5A. We further demonstrate that plexin-B3 activation by Sema5A mediates functional responses in plexin-B3-expressing cells (either fibroblasts, epithelial and primary endothelial cells). In addition, Sema5A can trigger the intracellular signalling of the hepatocyte growth factor/scatter factor receptor, Met, associated in a complex with plexin-B3. We thus conclude that Sema5A is able to elicit multiple functional responses through its receptor plexin-B3.
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