Key RNA Transcription Factors to Know for Biological Chemistry II

RNA transcription factors are essential for gene expression, guiding RNA Polymerase II in synthesizing mRNA from DNA. These factors, including TFIID and various activators and repressors, regulate transcription initiation and elongation, impacting protein production and cellular functions.

1. RNA Polymerase II

   • Responsible for synthesizing mRNA from DNA templates during transcription.
   • Requires various transcription factors for initiation and regulation of transcription.
   • Plays a critical role in the expression of protein-coding genes.

2. TFIID (including TBP)

   • A multi-subunit complex that recognizes and binds to the TATA box in the promoter region.
   • TBP (TATA-binding protein) is a key component that facilitates the assembly of the transcription machinery.
   • Acts as a platform for the recruitment of other general transcription factors and RNA Polymerase II.

3. TFIIA

   • Stabilizes the binding of TFIID to the promoter.
   • Helps to prevent the binding of repressors that could inhibit transcription.
   • Plays a role in the recruitment of additional transcription factors.

4. TFIIB

   • Acts as a bridge between TFIID and RNA Polymerase II.
   • Recognizes the BRE (TFIIB recognition element) in the promoter.
   • Essential for the formation of the transcription initiation complex.

5. TFIIE

   • Involved in the recruitment of TFIIH to the transcription complex.
   • Plays a role in the regulation of the transition from transcription initiation to elongation.
   • Helps to stabilize the transcription complex during the initiation phase.

6. TFIIF

   • Associates with RNA Polymerase II and helps to stabilize its binding to the promoter.
   • Facilitates the recruitment of TFIIE and TFIIH.
   • Plays a role in the transition from initiation to elongation of transcription.

7. TFIIH

   • Contains helicase activity that unwinds DNA at the transcription start site.
   • Involved in the phosphorylation of the RNA Polymerase II C-terminal domain (CTD), which is crucial for transcription elongation.
   • Plays a role in DNA repair processes.

8. Mediator complex

   • A large multi-protein complex that acts as a bridge between transcription factors and RNA Polymerase II.
   • Integrates signals from activators and repressors to regulate gene expression.
   • Facilitates the assembly of the transcription machinery at the promoter.

9. Activators (e.g., NF-κB, AP-1)

   • Proteins that enhance the transcription of specific genes by binding to enhancer regions.
   • Recruit coactivators and the transcription machinery to the promoter.
   • Play critical roles in cellular responses to signals such as stress, inflammation, and growth factors.

10. Repressors (e.g., NRSF/REST)

    • Proteins that inhibit gene transcription by binding to silencer regions or competing with activators.
    • Can recruit corepressors to the transcription complex to block transcription.
    • Important for maintaining tissue-specific gene expression and preventing inappropriate gene activation.

11. Enhancer-binding proteins

    • Bind to enhancer regions located far from the promoter to increase transcription levels.
    • Interact with the transcription machinery through looping of the DNA.
    • Play a crucial role in the regulation of gene expression in response to developmental and environmental signals.

12. Coactivators (e.g., p300/CBP)

    • Proteins that enhance transcription by interacting with activators and the transcription machinery.
    • Often have histone acetyltransferase activity, modifying chromatin structure to promote transcription.
    • Serve as a bridge between transcription factors and RNA Polymerase II.

13. Corepressors (e.g., NCoR, SMRT)

    • Proteins that inhibit transcription by interacting with repressors and the transcription machinery.
    • Often involved in the recruitment of histone deacetylases to modify chromatin and repress transcription.
    • Play a role in maintaining gene silencing and regulating developmental processes.

14. General transcription factors (GTFs)

    • Essential proteins required for the initiation of transcription by RNA Polymerase II.
    • Include TFIID, TFIIA, TFIIB, TFIIE, TFIIF, and TFIIH.
    • Work together to form the pre-initiation complex at the promoter.

15. Chromatin remodeling factors (e.g., SWI/SNF)

    • Complexes that alter chromatin structure to facilitate access to DNA for transcription.
    • Use ATP hydrolysis to reposition or evict nucleosomes.
    • Play a critical role in regulating gene expression by making DNA more accessible to transcription factors and RNA Polymerase II.