Split Driver Expression Patterns

Split drivers comprise at least two partial transcription factors that can reconstitute an active transcription factor when expressed in the same cell. By using different regulatory regions for each component, functional driver expression can be restricted to the intersection of the expression patterns of these regulatory regions. A wide range of regulatory regions have been combined with transcription factor DNA binding domains (DBDs) and Activation Domains (ADs) to form thousands of distinct constructs, referred to as hemidrivers. Millions of combinations are therefore possible, each targeting some precise subset of the many thousands of neurons in the Drosophila nervous system.

Researchers can identify split drivers for neurons of interest from the Targeting Splits section of a cell type Term Info page or by using similarity scores from a single neuron image. It is also possible to search directly for particular hemidrivers and combinations.

Similar to non-split drivers, VFB contains images and curated information about expression patterns for combinations. Each combination gets a standard name in VFB, reflecting the names of the component hemidrivers and any short names for the combination from the literature are added as synonyms (e.g. “P{VT017411-GAL4.DBD} ∩ P{VT019018-p65.AD} expression pattern” has_exact_synonym: SS02256").

VFB curation uses programmatic methods to generate expression statements for FlyLight hemidriver combinations. Combinations are validated against a local copy of the FlyLight dataset and loaded into FlyBase. VFB then links each expression pattern image and the curated expression information to an intersection of the two appropriate hemidrivers.