Regulation of Gene Expression

• Prokaryotic gene expression is primarily regulated at the level of initiation of gene transcription. In general, there is one protein per gene.
  • Sets of genes encoding proteins with related functions are organized into operons.
  • Each operon is under the control of a single promoter.
  • Repressors bind to the promoter to inhibit RNA polymerase binding.
  • Activators facilitate RNA polymerase binding to the repressor.
• Eukaryotic gene regulation occurs at several levels.
  • At the DNA structural level chromatin must be remodeled to allow access for RNA polymerase.
  • Transcription is regulated by transcription factors, which either enhance or restrict RNA polymerase access to the promoter.
  • RNA processing (including alternative splicing), transport from the nucleus to the cytoplasm, and translation are also regulated in eukaryotes.