Transcriptional Repressors

Transcriptional repressors are proteins that bind to specific sites on DNA and prevent transcription of nearby genes. (RNA can also inhibit transcription, but inhibitory RNAs are not usually called repressors.)

Most repressors inhibit the initiation of transcription. The following cartoons give a simple overview of the inititation of transcription, and show three ways that repressors can inhibit transcription.

SOME USEFUL GENERAL REVIEWS ON REPRESSORS:

The following two references describe details of how the Lac repressor binds DNA and represses transcription of the lac operon.
• Bell CE, Lewis M. 2001. The Lac repressor: a second generation of structural and functional studies. Curr Opin Struct Biol. 11: 19-25.
• Pace HC, Kercher MA, Lu P, Markiewicz P, Miller JH, Chang G, Lewis M. 1997. Lac repressor genetic map in real space. Trends Biochem Sci. 22: 334-339.

  The following reference describes the structures of other transcriptional regulators with different DNA-binding motifs than the Lac repressor.

• Huffman JL, Brennan RG. 2002. Prokaryotic transcription regulators: more than just the helix-turn-helix motif. Curr Opin Struct Biol. 12: 98-106.

  The following reference is a delightful short and very readible book that focuses upon how lambda repressor works.

• Ptashne, M. 2004. A Genetic Switch, 3rd edition. Phage Lambda Revisited. Cold Spring Harbor Laboratory Press, NY.