repressor

American  

[ri-pres-er] / rɪˈprɛs ər /

noun

1. represser.

2. Genetics. a protein that binds DNA at an operator site and thereby prevents transcription of one or more adjacent genes.

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repressor British  

/ rɪˈprɛsə /

noun

1. biochem a protein synthesized under the control of a repressor gene, which has the capacity to bind to the operator gene and thereby shut off the expression of the structural genes of an operon

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repressor Scientific  

/ rĭ-prĕs′ər /

1. A protein that binds to an operator, blocking transcription of an operon and the enzymes for which the operon codes.

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Etymology

Origin of repressor

From Latin, dating back to 1955–60; see origin at repress, -tor

Example Sentences

The repressor will bind the operator in the presence of lactose.

From Textbooks • Jun. 9, 2022

If lactose is absent, then the repressor binds to the operator to prevent transcription.

From Textbooks • Jun. 9, 2022

When tryptophan is absent, the repressor protein does not bind to the operator and the genes are transcribed.

From Textbooks • Jun. 9, 2022

When tryptophan is present in the cell, two tryptophan molecules bind to the trp repressor, which changes shape to bind to the trp operator.

From Textbooks • Jun. 9, 2022

In 1957, Pardee, Monod, and Jacob discovered that the lactose operon was controlled by a single master switch—a protein eventually called the repressor.

From "The Gene" by Siddhartha Mukherjee