The Trh promoter region is fused upstream of the Drosophila synthetic core promoter (DSCP) followed by the p65(AD)::Zip+ hemidriver (component of a 'split driver' system, contains the p65 activation domain). A Hsp70 transcriptional terminator is present.

A GAL4(DBD)::Zip- hemidriver (component of the 'Split GAL4' system, contains the GAL4 DNA-binding domain) has been inserted into the first, non-sex specific coding exon of dsx, such that the hemidriver is expressed under the control of endogenous dsx sequences.