A GAL4 Driver Resource for Developmental and Behavioral Studies on the Larval CNS of Drosophila

We report the larval CNS expression patterns for 6,650 GAL4 lines based on cis-regulatory regions (CRMs) from the Drosophila genome. Adult CNS expression patterns were previously reported for this collection, thereby providing a unique resource for determining the origins of adult cells. An illustrative example reveals the origin of the astrocyte-like glia of the ventral CNS. Besides larval neurons and glia, the larval CNS contains scattered lineages of immature, adult-specific neurons. Comparison of lineage expression within this large collection of CRMs provides insight into the codes used for designating neuronal types. The CRMs encode both dense and sparse patterns of lineage expression. There is little correlation between brain and thoracic lineages in patterns of sparse expression, but expression in the two regions is highly correlated in the dense mode. The optic lobes, by comparison, appear to use a different set of genetic instructions in their development. [Display omitted] •Larval GAL4 resource for behavioral and developmental studies•Recognizes sparse and dense codes for neuronal lineages•Facilitates tracking of cells through metamorphosis Containing only about 12,000 neurons, the larval nervous system of Drosophila is an important model for developmental and behavioral studies. Li et al. describe the larval nervous system expression patterns for a collection of 6,650 enhancer-GAL4 reporter lines. Because the adult nervous system expression has also been characterized for these lines, they allow the exploration of neuron and enhancer function through metamorphosis. They also provide insights into the genomic rules that govern the identity of neurons and neuronal lineages.