A conditional transgenic reporter of presynaptic terminals reveals novel features of the mouse corticospinal tract

Pasquale D'Acunzo, Aurora Badaloni, Mattia Ferro, Maddalena Ripamonti, Vincenzo Zimarino, Antonio Malgaroli, G. Giacomo Consalez

Research output: Contribution to journalArticle

Abstract

In many neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS), synaptic alterations precede the demise of the neuronal cell, making synapses a useful vantage point from which to monitor the onset and progression of clinical signs and pathological changes. While murine models of ALS display many features in common with the clinical picture observed in patients, corticospinal tract (CST) involvement is usually less severe in mice than the picture observed in humans. In this paper we describe the characterization of a new conditional transgenic line obtained by targeted integration of a GFP-VAMP2 fusion gene into the Rosa26 locus, and devised to permit the detection of genetically defined presynaptic terminals in wild type mice and murine models of neural disorders. This reporter molecule is selectively enriched in presynaptic boutons, significantly reducing the background signal produced by fibers of passage. The specific features of this reporter line allow us to strongly support the view that murine CST terminals give rise to very few direct contacts with spinal motor neurons. Moreover, the evidence described here reveals the existence of previously uncharacterized, putative direct connections between CST presynaptic boutons and Renshaw neurons in the spinal cord. These results constitute a proof of concept for the potential application of this indicator line to morphological analyses of wild type and diseased synapses.

Original languageEnglish
Article number50
JournalFrontiers in Neuroanatomy
Volume7
Issue numberJAN
DOIs
Publication statusPublished - Jan 7 2014

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Keywords

  • Amyotrophic lateral sclerosis
  • Axons
  • GFP labeled
  • Neurodegenerative
  • Presynaptic terminals
  • Reporter mouse
  • Synapses
  • Transgenic mice

ASJC Scopus subject areas

  • Anatomy
  • Neuroscience (miscellaneous)
  • Cellular and Molecular Neuroscience

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