Activator (genetics)

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An activator in genetics is a DNA -binding substance, e.g. B. the low molecular weight arabinose or regulator proteins , which bind to the operator binding site in the 3 'direction in front of the operator and thereby increase the affinity of the RNA polymerase to the promoter , whereby the transcription of the gene (or operon ) is activated . The activator is activated by a coactivator (signal substance) or inductor .

A distinction is made between constitutive and regulated activators.

example

Catabolite repression : The activator CAP (Catabolite Activator Protein), in the presence of the coactivator cAMP , activates the transcription of the lactose operon ( lac operon).

See also

Gene regulation

literature

Doris Freudig, Rolf Sauermost (Red.): Lexicon of Biology. Volume 1: A to Arjona. Study edition. Elsevier Spektrum Akademischer Verlag, Heidelberg et al. 2006, ISBN 3-8274-0326-X .