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Citation
Al-Anzi, B., Wyman, R.J. (2009). The Drosophila immunoglobulin gene turtle encodes guidance molecules involved in axon pathfinding.  Neural Dev. 4(): 31.
FlyBase ID
FBrf0209104
Publication Type
Research paper
Abstract

Neuronal growth cones follow specific pathways over long distances in order to reach their appropriate targets. Research over the past 15 years has yielded a large body of information concerning the molecules that regulate this process. Some of these molecules, such as the evolutionarily conserved netrin and slit proteins, are expressed in the embryonic midline, an area of extreme importance for early axon pathfinding decisions. A general model has emerged in which netrin attracts commissural axons towards the midline while slit forces them out. However, a large number of commissural axons successfully cross the midline even in the complete absence of netrin signaling, indicating the presence of a yet unidentified midline attractant.The evolutionarily conserved Ig proteins encoded by the turtle/Dasm1 genes are found in Drosophila, Caenorhabditis elegans, and mammals. In Drosophila the turtle gene encodes five proteins, two of which are diffusible, that are expressed in many areas, including the vicinity of the midline. Using both molecular null alleles and transgenic expression of the different isoforms, we show that the turtle encoded proteins function as non-cell autonomous axonal attractants that promote midline crossing via a netrin-independent mechanism. turtle mutants also have either stalled or missing axon projections, while overexpression of the different turtle isoforms produces invasive neurons and branching axons that do not respect the histological divisions of the nervous system.Our findings indicate that the turtle proteins function as axon guidance cues that promote midline attraction, axon branching, and axonal invasiveness. The latter two capabilities are required by migrating axons to explore densely packed targets.

PubMed ID
PubMed Central ID
PMC2739522 (PMC) (EuropePMC)
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Secondary IDs
    Language of Publication
    English
    Additional Languages of Abstract
    Parent Publication
    Publication Type
    Journal
    Abbreviation
    Neural Dev.
    Title
    Neural Development
    Publication Year
    2006-
    ISBN/ISSN
    1749-8104
    Data From Reference