Transcription can thus be regulated at two levels: the promoter level (cis regulation) and the polymerase level (trans regulation). These elements differ among bacteria and eukaryotes.

In eukaryotes, the "core" promoter for a gene transcribed by pol II is most often found immediately upstream (5′) of the start site of the gene. Most pol II genes have a TATA box (consensus ...

Regulated initiation of transcription to produce mRNA in eukaryotes requires the stepwise assembly of an elaborate multiprotein preinitiation complex consisting of the general transcription factors, ...