Transcriptional Control in Eukaryotic Cells

Transcription is an important level of control in eukaryotic cells, and this control requires a number of different types of proteins and regulatory elements. The initiation of eukaryotic transcription was discussed in detail in Chapter 13. Recall that general transcription factors and RNA polymerase assemble into a basal transcription apparatus, which binds to a core promoter located immediately upstream of a gene. The basal transcription apparatus is capable of minimal levels of transcription; transcriptional activator proteins are required to bring about normal levels of transcription. These proteins bind to a regulatory promoter, which is located upstream of the core promoter, and to enhancers, which may be located some distance from the gene (< Figure 16.21).

Transcriptional activators, coactivators and repressors

Transcriptional activator proteins stimulate transcription by facilitating the assembly or action of the basal transcription apparatus at the core promoter; the activators may interact directly with the basal transcription apparatus or indirectly

Activator binding site

(regulatory promoter)

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