Eukaryotes

• Why might transcription not occur?

  Repressor proteins can attach to the DNA of the promotor region, blocking the attachment site.
• Why transcription may not occur?

  • regulator protein may not be present
  • repressor protein binds to a regulator protein which prevents binding
• Gene activation in eukaryotes

  1. active genes are transcribed into mRNA.
  2. RNA polymerase binds to the promotor region to allow gene transcription.
  3. attachment of a regulator protein is required for a successful transcription
  4. repressor proteins may switch off the gene by binding to the regulator protein or to the promotor region preventing transcription