A searchable image resource ofDrosophilaGAL4-driver expression patterns with single neuron resolution

Abstract

Precise, repeatable genetic access to specific neurons via the GAL4/UAS system and related methods is a key advantage of Drosophila neuroscience. Neuronal targeting is typically documented using light microscopy of full GAL4 expression patterns, which mostly lack the single-cell resolution required for reliable cell type identification. Here we use stochastic GAL4 labeling with the MultiColor FlpOut approach to generate cellular resolution confocal images at large scale. We are releasing aligned images of 27,000 such adult central nervous systems.An anticipated use of this resource is to bridge the gap between electron microscopyidentified neurons and light microscopy-based intersectional genetic approaches such as the split-GAL4 system. Identifying the individual neurons that make up each GAL4 expression pattern improves the prediction of which GAL4 enhancer fragments best combine via split-GAL4 to target neurons of interest. To this end we have developed the NeuronBridge search tool, which matches these light microscope neuronal images to neurons in the recently published FlyEM hemibrain. This work thus provides a resource and search tool that will significantly enhance both the efficiency and efficacy of split-GAL4 targeting of EM-identified neurons and further advance Drosophila neuroscience.Meissner, et al., 2020Gen1 MCFO Phase 1 release

Distributed control of motor circuits for backward walking in Drosophila

“…Additionally, we included sparse driver lines likely to include any of the cell types identified in the trans-Tango experiments. For the sparsest lines in which a GCaMP6s response was observed, we identified the specific cell type that was MDN-responsive by matching the pattern of correlated voxels to a series of images of single cells obtained by stochastic labeling 24 using a driver line containing the same enhancer (Fig. 3c).…”

Distributed control of motor circuits for backward walking in Drosophila

“…To segment an MF neuron type, we obtained stochastic labelling images using GAL4 lines containing the same enhancers that were used for calcium imaging to drive expression of a MCFO reporter 22 . To segment an MT neuron type, we used images from the stochastic trans-Tango dataset in Fig.…”

The Drosophila Split Gal4 System for Neural Circuit Mapping

“…The coverage of neurons in the numerically simpler larval brain is likely to be better. Resources created to exploit the many thousands of enhancers represented in the GMR and VT collections will help distribute this effort (see for example Meissner et al, 2020 ), and methods for rationally identifying novel gene enhancers—or for making gene-specific Split Gal4 hemidrivers—may help realize a relatively complete catalog of Split Gal4 drivers. Where gaps persist and further specificity is required, further restriction using the Killer Zipper or other combinatorial strategies may also help (for examples see Pankova and Borst, 2017 ; Tison et al, 2019 ).…”

“…In this manner, Split Gal4 hemidrivers that target the cells lying at the intersection of two overlapping Gal4 expression patterns can be generated. Identifying CRMs that are likely to give an overlapping expression of Split Gal4 hemidrivers in cell types of interest has been greatly facilitated by the development of image registration and analysis tools, such as the color depth “MIP mask” tool (Otsuna et al, 2018 ), the Neuroanatomy Toolbox (Bates et al, 2020 ), and the recently released NeuronBridge software (Meissner et al, 2020 ). Such software tools can be used to align, compare, and search for similar expression patterns from confocal Z-stacks.…”