title: mGRASP enables mapping mammalian synaptic connectivity with light microscopy.
abstract: The GFP reconstitution across synaptic partners (GRASP) technique, based on functional complementation between two nonfluorescent GFP fragments, can be used to detect the location of synapses quickly, accurately and with high spatial resolution. The method has been previously applied in the nematode and the fruit fly but requires substantial modification for use in the mammalian brain. We developed mammalian GRASP (mGRASP) by optimizing transmembrane split-GFP carriers for mammalian synapses. Using in silico protein design, we engineered chimeric synaptic mGRASP fragments that were efficiently delivered to synaptic locations and reconstituted GFP fluorescence in vivo. Furthermore, by integrating molecular and cellular approaches with a computational strategy for the three-dimensional reconstruction of neurons, we applied mGRASP to both long-range circuits and local microcircuits in the mouse hippocampus and thalamocortical regions, analyzing synaptic distribution in single neurons and in dendritic compartments.
authors.affiliation: Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, USA. kimj@kist.re.kr
authors.forename: Jinhyun
authors.initials: J
authors.lastname: Kim
authors.forename: Ting
authors.initials: T
authors.lastname: Zhao
authors.forename: Ronald S
authors.initials: RS
authors.lastname: Petralia
authors.forename: Yang
authors.initials: Y
authors.lastname: Yu
authors.forename: Hanchuan
authors.initials: H
authors.lastname: Peng
authors.forename: Eugene
authors.initials: E
authors.lastname: Myers
authors.forename: Jeffrey C
authors.initials: JC
authors.lastname: Magee
mesh_terms: D000818:Animals; D003712:Dendrites; D018274:Electroporation; D005822:Genetic Vectors; D049452:Green Fluorescent Proteins / Q000378:metabolism*; D006624:Hippocampus / Q000166:cytology*; D051379:Mice; D008853:Microscopy; D008969:Molecular Sequence Data; D050506:Mutant Chimeric Proteins; D013003:Somatosensory Cortex / Q000502:physiology; D013569:Synapses / Q000502:physiology*; D020651:Ventral Thalamic Nuclei / Q000502:physiology
chemical_list: D050506:Mutant Chimeric Proteins; D049452:Green Fluorescent Proteins