A ChAT promoter regulates expression of a GAL4(DBD)::Zip- hemidriver (component of the 'Split GAL4' system, contains the GAL4 DNA-binding domain).
ort promoter sequences containing conserved regions C1-C3 are fused upstream of sequences encoding a GAL4(AD)::Zip+ hemidriver (component of a 'split driver' system, contains the GAL4 activation domain).