Consequences of mutations in the upstream promoter region

    The effect of a point  mutation at each position can be measured by comparing the level of mRNA transcription relative to the un-mutated gene [vertical scale]. The graph shows strong reduction of transcription level by mutations in the promoter regions at -10 (ATATAA) & -35 (GGCCAATC), and at an upstream enhancer region. Note that mutations at two sites immediately 5' to the -35 promoter sharply increase transcription. A mutation at the start point of transcription () turns off transcription entirely. 

    Note that the large majority of mutations in this region have no measurable effect on transcription. Dots indicate positions where the consequences of mutations are unknown.