TY - JOUR
T1 - A conditional transgenic reporter of presynaptic terminals reveals novel features of the mouse corticospinal tract
AU - D'Acunzo, Pasquale
AU - Badaloni, Aurora
AU - Ferro, Mattia
AU - Ripamonti, Maddalena
AU - Zimarino, Vincenzo
AU - Malgaroli, Antonio
AU - Consalez, G. Giacomo
PY - 2014/1/7
Y1 - 2014/1/7
N2 - 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.
AB - 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.
KW - Amyotrophic lateral sclerosis
KW - Axons
KW - GFP labeled
KW - Neurodegenerative
KW - Presynaptic terminals
KW - Reporter mouse
KW - Synapses
KW - Transgenic mice
UR - http://www.scopus.com/inward/record.url?scp=84892592534&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84892592534&partnerID=8YFLogxK
U2 - 10.3389/fnana.2013.00050
DO - 10.3389/fnana.2013.00050
M3 - Article
AN - SCOPUS:84892592534
VL - 7
JO - Frontiers in Neuroanatomy
JF - Frontiers in Neuroanatomy
SN - 1662-5129
IS - JAN
M1 - 50
ER -