Certain sequence characteristics have been observed in bidirectional promoters, including a lack of TATA boxes, an abundance of CpG islands, and a symmetry around the midpoint of dominant Cs and As on one side and Gs and Ts on the other. A motif with the consensus sequence of TCTCGCGAGA, also called the CGCG element, was recently shown to drive PolII-driven bidirectional transcription in CpG islands. CCAAT boxes are common, as they are in many promoters that lack TATA boxes. In addition, the motifs NRF-1, GABPA, YY1, and ACTACAnnTCCC are represented in bidirectional promoters at significantly higher rates than in unidirectional promoters. The absence of TATA boxes in bidirectional promoters suggests that TATA boxes play a role in determining the directionality of promoters, but counterexamples of bidirectional promoters do possess TATA boxes and unidirectional promoters without them indicates that they cannot be the only factor.
certain sequence characteristics have been observed in bidirectional promoters including a lack of tata boxes an abundance of cpg islands and a symmetry around the midpoint of dominant cs and as on one side and gs and ts on the other a motif with the consensus sequence of tctcgcgaga also called the cgcg element was recently shown to drive polii-driven bidirectional transcription in cpg islands ccaat boxes are common as they are in many promoters that lack tata boxes in addition the motifs nrf-1 gabpa yy1 and actacanntccc are represented in bidirectional promoters at significantly higher rates than in unidirectional promoters the absence of tata boxes in bidirectional promoters suggests that tata boxes play a role in determining the directionality of promoters but counterexamples of bidirectional promoters do possess tata boxes and unidirectional promoters without them indicates that they cannot be the only factor