The pipTA entry in FlyBase represents an artificial transcriptional activator ('driver') that includes the DNA-binding domain from the pip gene of Streptomyces coelicolor and a transcriptional activation domain from the Herpes simplex virus Type 1 VP16 gene. The pip DNA-binding domain binds specifically to the pipO DNA sequence, and thus pipO and pipTA form a binary expression system that can be used to control the spatial and temporal expression of a gene of interest: a transgene or modified endogenous locus carrying the target gene of interest downstream of pipO sequences is combined with a second transgene or modified endogenous locus encoding the pipTA driver. The activity of the pipTA driver can potentially be suppressed by an antibiotic of the streptogramin group, such as pristinamycin or virginiamycin: upon binding to the streptogramin group antibiotic it is expected that pipTA will undergo a conformational change preventing it from binding the pipO sequence, thus reducing or preventing its ability to induce transcription (PMID:11062442). The exact sequence of the driver may differ depending on the particular transgene or modified endogenous locus being used. In particular, the number of VP16 activation domains present may vary, and/or the VP16 activation domains may contain mutations that alter the strength of transcriptional activation.