Enhancer-GAL4 Database Yields Subsets of Gene Expression

Presenter: David Bauer, Kris Haenderson, Allison Wilbur, Biology

Enhancers and suppressors are major controls in the tempro-spatial expression of a gene. Prior work has shown that enhancers may be made up of small modules, each driving only a small subset of expression in an overall pattern that we associate with a gene. The Rubin lab at Janelia Farms Research Center created over 70,000 fragment sequences from more than 1,100 neural gene regions. These fragment enhancer sequences were used to generate site-specific transgenic GAL4 expressing Drosophila lines. These lines are currently being screened by several collaborating labs for their ability to function as transcriptional enhancers to drive limited subsets of UAS-GFP expression. Our lab’s role is to screen Drosophila embryos for neural expression patterns of the transgenic enhancer fragment lines. As a test analysis, we took a subset of 82 individual fragment enhancer lines derived from seven gene regions in embryonic nerve cords (VNC). These 82 lines produced 77% of fragments with expression in the VNC. Within that expressing set, 62% drove small patterns of less than ten cells per hemisegment. This data complements the screening results collaborative labs are finding in Drosophila larval brains. Together, these results show that the theory of enhancers being a set of modules acting in concert to yield an overall pattern of gene expression seems quite likely. The end result should be a valuable tool that can be used for studies of gene control, patterning, and neuronal circuitry.