Model of Xenopus rhodopsin transcriptional activation. Nrl binds to the rhodopsin promoter via a highly conserved NRE site (TGCTGAnnC) that is immediately upstream of the TATA binding site. Crx binds independently to two adjacent sites (G/CTTA). This combination synergistically activates transcription with each Crx contributing equally to the overall activity. The Ret1 site (CCAATTA) mediates Rax protein binding to stimulate transcription.
Reks et al. BMC Molecular Biology 2014 15:4 doi:10.1186/1471-2199-15-4