title: Dynamic labelling of neural connections in multiple colours by trans-synaptic fluorescence complementation.
abstract: Determining the pattern of activity of individual connections within a neural circuit could provide insights into the computational processes that underlie brain function. Here, we develop new strategies to label active synapses by trans-synaptic fluorescence complementation in Drosophila. First, we demonstrate that a synaptobrevin-GRASP chimera functions as a powerful activity-dependent marker for synapses in vivo. Next, we create cyan and yellow variants, achieving activity-dependent, multi-colour fluorescence reconstitution across synapses (X-RASP). Our system allows for the first time retrospective labelling of synapses (rather than whole neurons) based on their activity, in multiple colours, in the same animal. As individual synapses often act as computational units in the brain, our method will promote the design of experiments that are not possible using existing techniques. Moreover, our strategies are easily adaptable to circuit mapping in any genetic system.
authors.affiliation: Howard Hughes Medical Institute and Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York 10032, USA.
authors.forename: Lindsey J
authors.initials: LJ
authors.lastname: Macpherson
authors.affiliation: Department of Neurobiology, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Emanuela E
authors.initials: EE
authors.lastname: Zaharieva
authors.affiliation: Department of Neurobiology, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Kearney
authors.affiliation: Department of Neurobiology, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Michael H
authors.initials: MH
authors.lastname: Alpert
authors.affiliation: Section on Neuronal Connectivity, Laboratory of Gene Regulation and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA.
authors.forename: Tzu-Yang
authors.initials: TY
authors.lastname: Lin
authors.affiliation: Howard Hughes Medical Institute and Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York 10032, USA.
authors.forename: Zeynep
authors.initials: Z
authors.lastname: Turan
authors.affiliation: Section on Neuronal Connectivity, Laboratory of Gene Regulation and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA.
authors.forename: Chi-Hon
authors.initials: CH
authors.lastname: Lee
authors.affiliation: Department of Neurobiology, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Marco
authors.identifier: http://orcid.org/0000-0003-2132-0639
authors.initials: M
authors.lastname: Gallio
mesh_terms: D000818:Animals; D004330:Drosophila / Q000737:chemistry / Q000502:physiology*; D005453:Fluorescence; D049452:Green Fluorescent Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D018613:Microscopy, Confocal; D009474:Neurons / Q000737:chemistry* / Q000502:physiology; D013194:Staining and Labeling / Q000295:instrumentation / Q000379:methods*; D013569:Synapses / Q000737:chemistry* / Q000502:physiology
chemical_list: D049452:Green Fluorescent Proteins