The GAL4(DBD)::nMagHigh1 entry in FlyBase represents a hemidriver that contains the DNA-binding domain from the Saccharomyces cerevisiae GAL4 gene ( SGDID:S000006169 ) fused to 'nMagHigh1', a negatively charged engineered domain that can heterodimerize with a compatible positively charged 'pMag'-type domain upon stimulation with blue light (for details of nMagHigh1 see PMID:25708714). GAL4(DBD)::nMagHigh1 forms one half of the 'ShineGAL4' split-GAL4 system: when combined in vivo with a hemidriver containing a transcriptional activation domain fused to a compatible pMag-type domain and exposed to blue light, the light-induced interaction between the nMag/pMag pair can reconstitute a functional transcriptional activator that can drive transcription of a downstream gene of interest. Since transcription is only activated at the intersection of the expression patterns of the two hemidrivers and upon activation by light, the ShineGAL4 system can be used to drive expression in a restricted pattern (FBrf0252177). The reconstituted transcriptional activator binds specifically to the UAS regulatory sequence due to the presence of the GAL4 DNA-binding domain. The exact sequence of the GAL4(DBD)::nMagHigh1 hemidriver may differ depending on the particular transgene or modified endogenous locus being used. In particular, the number of copies of the nMagHigh1 domain may vary, altering the strength of interaction with a compatible pMag-containing hemidriver in the presence of blue light.