Genome-wide detection of a TFIID localization element from an initial human disease mutation.|
National Human Genome Research Institute, USA
Eukaryotic core promoters are often characterized by the presence of consensus motifs such as the TATA box or initiator elements, which attract and direct the transcriptional machinery to the transcription start site. However, more than 38% of mammalian promoters are not associated with a known consensus motif, suggesting that undiscovered regulatory motifs exist in the genome. We previously identified a mutation in the human Ankyrin-1 (ANK-1) promoter that causes the disease Ankyrin deficient Hereditary Spherocytosis (HS). Although the ANK-1 promoter is CpG rich, no discernible basal promoter elements were previously identified. We showed that the HS mutation disrupted the binding of the transcription factor TFIID, the major component of the pre-initiation complex. We hypothesized that the mutation identified a candidate promoter element with a larger role in gene regulation. We examined 17,181 human promoters for the experimentally validated binding site, called the TFIID localization sequence (DLS) and found significantly more genes with DLS than TATA motifs. Mutational analyses of DLS sequences confirmed their functional significance, as did the addition of a DLS site to a minimal Sp1 promoter. Our results demonstrate novel promoter elements can be identified on a genome-wide scale through observations of regulatory disruptions that cause human disease.