Transcription start sites, promoter and enhancer regions of the of human OTC gene are described. We report the first patient in which the only variation found was a nucleotide substitution in promoter region.
We found that transcriptional activity of human OTC promoter depends on an upstream enhancer. The promoter – enhancer interaction contributes to tissue specific expression of OTC in the liver.
A unique nucleotide substitution in the promoter does not affect the function of the promoter alone but it disrupts its interaction with the enhancer.