Tetanus toxin light chain has been used for some time as a genetically-encoded tool to inhibit neurotransmission and thereby dissect mechanisms underlying neural circuit formation and function. In addition to cleaving v-SNARE proteins involved in axonal neurotransmitter release, tetanus toxin light chain can also block activity-dependent dendritic exocytosis. The application of tetanus toxin light chain as a research tool in mammalian models, however, has been limited to a small number of cell types. Here we have induced expression of tetanus toxin light chain in a very small number of fluorescently labeled neurons in many regions of the adult mouse brain. This was achieved by crossing SLICK (single-neuron labeling with inducible cre-mediated knockout) transgenic lines with RC::Ptox mice that have Cre recombinase-controlled expression of the tetanus toxin light chain. Using this system we have examined the cell-autonomous effects of tetanus toxin light chain expression on dendritic spines in vivo. We find that dendritic spine density is reduced by 15% in tetanus toxin expressing hippocampal CA1 pyramidal cells, while spine morphology is unaltered. This effect is likely to be a consequence of inhibition of activity-dependent dendritic exocytosis and suggests that on-going plasticity-associated exocytosis is required for long-term dendritic spine maintenance in vivo. © 2013 Elsevier Ireland Ltd.
CITATION STYLE
Heimer-McGinn, V., Murphy, A. C. H., Kim, J. C., Dymecki, S. M., & Young, P. W. (2013). Decreased dendritic spine density as a consequence of tetanus toxin light chain expression in single neurons in vivo. Neuroscience Letters, 555, 36–41. https://doi.org/10.1016/j.neulet.2013.09.007
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