Super-Resolution Dynamic Imaging of Dendritic Spines Using a Low-Affinity Photoconvertible Actin Probe

Ignacio Izeddin (1) , Christian G Specht (2) , Mickaël Lelek (3) , Xavier Darzacq (4) , Antoine Triller (2) , Christophe Zimmer (3) , Maxime Dahan (5)

1 LKB (Jussieu) - Laboratoire Kastler Brossel
2 Biologie Cellulaire de la Synapse Normale et Pathologique
3 Imagerie et Modélisation - Imaging and Modeling
4 REG - Régulation de l'expression génétique
5 LKB (Lhomond) - Laboratoire Kastler Brossel

The actin cytoskeleton of dendritic spines plays a key role in morphological aspects of synaptic plasticity. The detailed analysis of the spine structure and dynamics in live neurons, however, has been hampered by the diffraction-limited resolution of conventional fluorescence microscopy. The advent of nanoscopic imaging techniques thus holds great promise for the study of these processes. We implemented a strategy for the visualization of morphological changes of dendritic spines over tens of minutes at a lateral resolution of 25 to 65 nm. We have generated a low-affinity photoconvertible probe, capable of reversibly binding to actin and thus allowing long-term photoactivated localization microscopy of the spine cytoskeleton. Using this approach, we resolve structural parameters of spines and record their long-term dynamics at a temporal resolution below one minute. Furthermore, we have determined changes in the spine morphology in response to pharmacologically induced synaptic activity and quantified the actin redistribution underlying these changes. By combining PALM imaging with quantum dot tracking, we could also simultaneously visualize the cytoskeleton and the spine membrane, allowing us to record complementary information on the morphological changes of the spines at super-resolution.

Domains: Santé publique et épidémiologie

Ignacio Izeddin, Christian G Specht, Mickaël Lelek, Xavier Darzacq, Antoine Triller, et al.. Super-Resolution Dynamic Imaging of Dendritic Spines Using a Low-Affinity Photoconvertible Actin Probe. PLoS ONE, 2011, 6 (1), pp.e15611. ⟨10.1371/journal.pone.0015611⟩. ⟨pasteur-02081263⟩