title: Digital in vivo 3D atlas of the antennal lobe of Drosophila melanogaster.
abstract: As a model for primary olfactory perception, the antennal lobe (AL) of Drosophila melanogaster is among the most thoroughly investigated and well-understood neuronal structures. Most studies investigating the functional properties and neuronal wiring of the AL are conducted in vivo, although so far the AL morphology has been mainly analyzed in vitro. Identifying the morphological subunits of the AL-the olfactory glomeruli-is usually done using in vitro AL atlases. However, the dissection and fixation procedure causes not only strong volumetric but also geometrical modifications; the result is unpredictable dislocation and a distortion of the AL glomeruli between the in vitro and in vivo brains. Hence, to characterize these artifacts, which are caused by in vitro processing, and to reliably identify glomeruli for in vivo applications, we generated a transgenic fly that expresses the red fluorescent protein DsRed directly fused to the presynaptic protein n-synaptobrevin, under the control of the pan-neuronal promotor elav to label the neuropil in the live animal. Using this fly line, we generated a digital 3D atlas of the live Drosophila AL; this atlas, the first of its kind, provides an excellent geometric match for in vivo studies. We verified the identity of 63% of AL glomeruli by mapping the projections of 34 GAL4-lines of individual chemosensory receptor genes. Moreover, we characterized the innervation patterns of the two most frequently used GAL4-lines in olfactory research: Orco- and GH146-GAL4. The new in vivo AL atlas will be accessible online to the neuroscience community.
authors.affiliation: Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, 07745, Jena, Germany.
authors.forename: Veit
authors.initials: V
authors.lastname: Grabe
authors.forename: Antonia
authors.initials: A
authors.lastname: Strutz
authors.forename: Amelie
authors.initials: A
authors.lastname: Baschwitz
authors.forename: Bill S
authors.initials: BS
authors.lastname: Hansson
authors.forename: Silke
authors.initials: S
authors.lastname: Sachse
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D057506:Arthropod Antennae / Q000033:anatomy & histology* / Q000378:metabolism; D001921:Brain / Q000033:anatomy & histology / Q000378:metabolism; D001931:Brain Mapping; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D004331:Drosophila melanogaster / Q000033:anatomy & histology*; D021621:Imaging, Three-Dimensional; D066298:In Vitro Techniques; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D009415:Nerve Net / Q000033:anatomy & histology* / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D029721:Drosophila Proteins; C557617:GAL4 protein, Drosophila; D008164:Luminescent Proteins; D014157:Transcription Factors; C413663:fluorescent protein 583
keywords: Drosophila melanogaster; glomeruli; in vitro artifacts; in vivo neuropil marker; olfactory system