This video shows light microscopy images of some of the top split-GAL4 lines that express specific cell types. Images were created by averaging together one or more aligned images for each line. The color indicates depth in the brain. Credit: FlyLight/HHMI Janelia Research Campus

The holidays may be over, but neuroscientists are getting a special gift to kick off the new year: access to a greatest hits collection from one of Janelia’s longest running and successful Project Teams.

Janelia’s FlyLight Project Team, which has worked for more than a decade to create tools to study the fly brain, is making a core collection of their best genetically engineered fly strains available to researchers worldwide through the Bloomington Drosophila Stock Center. The brain images of these flies, along with hundreds of thousands of images from thousands of additional fly lines, are also now freely accessible through Janelia websites.

These tools – the result of work by hundreds of Janelians and collaborators – will allow fly scientists all over the world to test how individual neurons control behavior. These insights into the fly brain could help scientists better understand how actions are carried out by the brains of larger animals, including humans.

“It’s putting tools into people’s hands, in a way that will help their research and help the community as a whole move forward,” says Geoffrey Meissner, senior manager of Project Pipeline Support at Janelia, who was the project scientist for FlyLight. “Science is a collaborative effort: we stand on the shoulders of giants, and we want to help lift people up as well.”

A team science effort

While research into the fly brain is continuing at Janelia, the release of the fly lines and images marks the conclusion of the FlyLight Project Team, one of the first project teams established at the research campus. These teams bring together dozens of Janelians and visiting scientists for years at a time to take on large-scale efforts that have the potential to transform entire scientific fields but can’t be accomplished in a traditional academic environment or by a single lab. The resulting tools, data, and knowledge are shared widely with the scientific community.

- Geoffrey Meissner, senior manager of Project Pipeline Support at Janelia,
who was the project scientist for FlyLight

Since FlyLight’s inception in 2008, the team and collaborators have generated thousands of genetically engineered fly strains and brain images, enabling researchers to precisely home in on individual neurons to figure out which cells are controlling specific behaviors. Using these tools, researchers have gained greater insight into how flies see and navigate complex environments, make life-altering decisions like courting their mates, and how memories are represented in the nervous system, among dozens of other findings that could give scientists insight into the functioning of larger brains, including the human brain.  

With FlyLight winding down, the team decided to make available a collection of the best of these fly strains, covering a wide range of cell types, so everyone in the scientific community can benefit from these efforts – a core tenet of all the project teams and Janelia’s commitment to open science, says Wyatt Korff, Janelia’s senior director of project teams.

“By partnering with Bloomington, we can ensure that the tools we generated, which we have internally found incredibly valuable, and we know will be incredibly valuable for the whole scientific community, accessible to everyone,” he says. “This collection of the best of the FlyLight Project Team is going to be out there for anyone to use.”

The greatest hits

The 3,000 FlyLight strains at Bloomington enable scientists to use the split-GAL4 method to identify single neurons or cell types in the adult fly brain. These strains cover many parts of the central nervous system and two-thirds of them have not previously been available outside Janelia.

“These 3,000 lines in the omnibus collection are the best of the best – the greatest hits of the split-GAL4 approach,” Korff says.

An additional 1,000 larval fly strains created by Janelia researchers are also being shared for the first time.

By maintaining and providing access to these fly strains, the Bloomington Drosophila Stock Center is helping to preserve the years of work that went into developing the lines and characterizing their neurons.

As the national repository for Drosophila strains, Bloomington is supported by the National Institutes of Health’s Office of the Director, the National Institute of General Medical Sciences and the National Institute of Child Health and Human Development. Because the FlyLight strains are important to understanding brain function, the National Institute of Neurological Disorders and Stroke has been providing special funding for the distribution of previously donated FlyLight strains. Additional support from HHMI enables Bloomington to maintain and distribute the new strains through August 2026.

Since 2017, Bloomington has shipped more than 300,000 samples of these strains to research groups in more than 50 countries. The center anticipates the new strains will also be popular among brain researchers.

“Getting these stocks and making them available to everyone is closing the loop of all the amazing work from Janelia,” says Cale Whitworth, co-director of the Bloomington Drosophila Stock Center.

The accompanying images

In addition to the flies themselves, FlyLight is releasing light microscopy images of their brains and 300,000 images of the brains of other fly strains that the team created over the past decade. Although some of these split-GAL4 combinations are no longer available, stocks for all the split halves were also deposited at Bloomington, so researchers can use these data and Janelia’s NeuronBridge website to search for neurons of interest and create their own fly strains – essentially giving scientists access to the project team’s lab notebook.  

These images join previous image releases by the FlyLight Project Team. In total, the team has made 540,000 brain images from 230,000 fly samples available to researchers.

“FlyLight’s mission has been to develop tools to study the fly brain, to develop lines that give us this specific cell-type targeting,” Meissner says. “We are sharing the precise tools to get the job done --to see your neurons and manipulate them in a precise way, to know exactly what you are doing when you make a change in the fly and see what happens. This is making those tools available to the broader fly community.”

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Citation

Geoffrey W. Meissner et al. “A split-GAL4 driver line resource for Drosophila CNS cell types.” Posted on bioRxiv on January 10, 2024. DOI: 10.1101/2024.01.09.574419