An Overview of Bidirectional Promoters

A promoter is a region of DNA to which RNA polymerase binds in the presence of transcription factors; the RNA polymerase then transcribes the DNA in the 5´ to 3´ direction. Two genes that are transcribed in opposite directions, and for which their 5´ ends are within 1000 base pairs of each other are said to be in a head-to-head configuration. The significance of this configuration is that since the promoter region lies upstream of the 5´ end of the corresponding gene, it is likely that the promoter regions for the two genes lie in the region between the 5´ ends; such a region is called a bidirectional promoter region. Bidirectional promoters are interesting because they aid in localizing promoter regions, and also suggest the possibility of co-regulation of the genes that bound the bidirectional promoter. In this talk we discuss the history of bidirectional promoter research, and broad scope of current research in this area, including recent work that suggests that certain cancer genes are enriched in bidirectional promoters, and also discuss a method for feature-based classification of human bidirectional promoters.