| Abstract |
The function of the cerebral cortex relies on several stereotypical long-distance
projections, which originate from excitatory projection neurons that represent the largest
portion of all cortical neurons. Axonal tracts, originating from projection neurons
connect areas essential for brain function and they are also important for the final
structure of the central nervous system.
Cortical efferents (corticothalamic axons or CTAs) are expressing high levels of
Transient Axonal Glycoprotein-1 or Contactin-2 (TAG-1/Cntn2), a neuronal recognition
molecule of the immunoglobulin superfamily which is involved in neurogenesis, neurite
outgrowth and fasciculation. Among other neuronal subpopulations, it is expressed early
by pioneer neurons in the preplate and later on in the marginal zone and subplate of the
developing cortex.
To study the formation of several axonal tracts in the mouse central nervous system, we
generated the transgenic mouse line Tag1loxP-GFP-loxP-DTA. These mice express GFP under
the Tag-1 promoter, also encompassing the coding sequence of Diptheria Toxin subunit
A (DTA) under quiescence. Upon crossing with the neocortex-specific Emx1::Cre line,
GFP expression is eliminated and the toxin is expressed in TAG-1+ neurons cells
resulting in their death.
Cortical lamination deficits and aberrant axonal connectivity in the brain is a main cause
of neurodevelopmental disorders in human. Emx1::Cre;Tag-1::DTA mice have reduced
CTAs and their analysis in embryonic and postnatal stages will give useful information
for the role of these axons in the brain development.
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Analysis of a novel transgenic mouse line with defective fiber tracts
