title: Three-dimensional imaging of Drosophila motor synapses reveals ultrastructural organizational patterns.
abstract: We combined cryo-preservation of intact Drosophila larvae and electron tomography with comprehensive segmentation of key features to reconstruct the complete ultrastructure of a model glutamatergic synapse in a near-to-native state. Presynaptically, we detail a complex network of filaments that connects and organizes synaptic vesicles. We link the complexity of this synaptic vesicle network to proximity to the active zone cytomatrix, consistent with the model that these protein structures function together to regulate synaptic vesicle pools. We identify a net-shaped network of electron-dense filaments spanning the synaptic cleft that suggests conserved organization of trans-synaptic adhesion complexes at excitatory synapses. Postsynaptically, we characterize a regular pattern of macromolecules that yields structural insights into the scaffolding of neurotransmitter receptors. Together, these analyses reveal an unexpected level of conservation in the nanoscale organization of diverse glutamatergic synapses and provide a structural foundation for understanding the molecular machines that regulate synaptic communication at a powerful model synapse.
authors.affiliation: a Laboratory of Cell and Molecular Biology , University of Wisconsin-Madison , Madison , WI , USA.
authors.forename: Hong
authors.initials: H
authors.lastname: Zhan
authors.affiliation: b Cell and Molecular Biology Training Program , University of Wisconsin-Madison , Madison , WI , USA.
authors.forename: Joseph
authors.initials: J
authors.lastname: Bruckner
authors.affiliation: a Laboratory of Cell and Molecular Biology , University of Wisconsin-Madison , Madison , WI , USA.
authors.forename: Ziheng
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: a Laboratory of Cell and Molecular Biology , University of Wisconsin-Madison , Madison , WI , USA.|b Cell and Molecular Biology Training Program , University of Wisconsin-Madison , Madison , WI , USA.|c Laboratory of Genetics , University of Wisconsin-Madison , Madison , WI , USA.
authors.forename: Kate
authors.initials: K
authors.lastname: O'Connor-Giles
mesh_terms: D000818:Animals; D004330:Drosophila; D055032:Electron Microscope Tomography; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007814:Larva; D009469:Neuromuscular Junction / Q000648:ultrastructure*; D013569:Synapses / Q000648:ultrastructure*
keywords: Neuromuscular junction; active zone; electron tomography; high-pressure freezing; postsynaptic density; presynaptic cytomatrix; synaptic cleft; synaptic vesicles