Control of Gene Expression

• Main idea: To control how much of a gene gets used, the cell usually controls whether transcription starts or not

• How it works: Special proteins (regulatory proteins) bind to the DNA

  • These proteins can either block or enhance the transcription process, thereby determining the level of gene expression

• In bacteria (prokaryotes): They adjust gene use based on environmental conditions, allowing them to quickly respond to changes

• In complex cells (eukaryotes, like humans): Regulatory proteins that control gene use to keep the body stable and balanced (homeostasis)

  • Interacting with many sequences in the gene’s promoter region, such as chromatin remodeling and RNA processing

Interactions in Expression:

Regulatory Proteins:

They control which genes get turned on or off by attaching to specific DNA sequences

• They grab onto the DNA at a wide opening called the major groove

• They have specialized structures (called motifs) that fit perfectly into the DNA

• Transcription factors: Proteins that bind to specific DNA sequences to regulate the transcription of genetic information from DNA to messenger RNA. have to have 2D because they require a specific spatial orientation to effectively interact with the DNA's major groove, allowing them to precisely recognize and bind to their target sequences.

• Enhancers and silencers: DNA elements that can increase or decrease the transcription levels of genes, often located far away from the promoter region.

• Co-activators and co-repressors: Proteins that do not bind DNA directly but assist transcription factors in enhancing or suppressing transcription.