Biology as Poetry: Genetics

Bacteriophage Ecology Group

Negative Control (of gene expression)

Transcription factor binding to DNA that results in decreased rates of transcription.

In negative control of gene expression the protein involved either gets in the way of RNA polymerase binding to a promoter (transcription initiation block) or inhibits the elongation step of transcription.

Key is that the occurrence of transcription is negatively affected by the protein binding rather than any issues relevant to the circumstances under which protein binding is or is not possible (e.g., protein activation or corepression). What matters simply is that a protein gets in the way of transcription and therefore of gene expression.

See for example inducible operon, Lac operon, corepressed operon, and Trp operon. Contrast with positive control of gene expression. Note, also in contrast, the concepts simply of positive control and negative control.

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