<Dd> The process is more complicated, and at least seven different factors are necessary for the binding of an RNA polymerase II to the promoter . </Dd> <P> Promoters represent critical elements that can work in concert with other regulatory regions (enhancers, silencers, boundary elements / insulators) to direct the level of transcription of a given gene . A promoter is induced in response to changes in abundance or conformation of regulatory proteins in a cell, which enable activating transcription factors to recruit RNA polymerase . </P> <P> As promoters are typically immediately adjacent to the gene in question, positions in the promoter are designated relative to the transcriptional start site, where transcription of DNA begins for a particular gene (i.e., positions upstream are negative numbers counting back from - 1, for example - 100 is a position 100 base pairs upstream). </P> <P> In the cell nucleus, it seems that promoters are distributed preferentially at the edge of the chromosomal territories, likely for the co-expression of genes on different chromosomes . Furthermore, in humans, promoters show certain structural features characteristic for each chromosome . </P>

Where is dna located how does it express itself