1
$\begingroup$

Wikipedia has two images, of a eukaryotic gene and of a prokaryotic gene. They show the difference that the prokaryotic gene also has an operator while the eukaryotic gene does not. Both also have enhancers and silencers separately. I thought enhancers and silencers were types of operators. Is this wrong?

$\endgroup$
1
  • 1
    $\begingroup$ Operators were classically defined by cis-Dominant mutations, located upstream of the protein-coding region of a gene, that rendered the gene's expression constitutive, or un-regulated. This was before the promoter was defined as a separate control element. $\endgroup$ – mdperry Jul 22 '15 at 23:41
1
$\begingroup$

Enhancers and silencers are binding sequences for transcriptional activators or repressors, in which case the sequence is often located some distance upstream or downstream of the gene it regulates. See regulation of transcription for information about how these interact with their target genes (through DNA bending, mediator, etc.). A note about enhancers and silencers, though, they're not necessarily required for transcription: they help the gene attain robust up- or down-regulation of transcription.

The operator, on the other hand, influences whether the promoter will do something, or nothing. If we're talking about inducible systems, the repressor is bound to the operator, blocking action to/from the promoter (an inducer will bind the repressor and keep the operator from blocking the promoter). If we're talking about a repressible system, the repressor will need a corepressor to bind the operator to abrogate transcription by blocking action to/from the promoter.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.