Multiple domains for initiator binding proteins TFII-I and YY-1 are present in the initiator and upstream regions of the rat XDH/XO TATA-less promoter.

We previously reported that the TATA-less rat xanthine dehydrogenase/oxidase (XDH/XO) promoter is organized with multiple initiator elements (Inr 1, 2, 3 and 4). Additionally, we identified six factor binding footprints in the upstream region of this promoter (FP 1-FP 6), two of which (FP 2 and FP 4) we showed to be C/EBP binding sites. In this report we continue our characterization of the XDH/XO promoter, detailing other cis elements which comprise the Inr and upstream binding factors. Interestingly, multiple binding domains for known initiator binding proteins, YY-1 and USF-related factor/TFII-I, have been identified which potentially play an important role in transcription initiation.