Podcast
Questions and Answers
Which transcription factor is the first to bind to the promoter during eukaryotic transcription?
Which transcription factor is the first to bind to the promoter during eukaryotic transcription?
What is the role of TBP in the transcription process?
What is the role of TBP in the transcription process?
Which complex helps recruit RNA polymerase II to the promoter region?
Which complex helps recruit RNA polymerase II to the promoter region?
What is the significance of the 5' cap added to mRNA during processing?
What is the significance of the 5' cap added to mRNA during processing?
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Which transcription factor complex possesses ATPase activity during the initiation phase?
Which transcription factor complex possesses ATPase activity during the initiation phase?
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What function does TF2S serve during transcription elongation?
What function does TF2S serve during transcription elongation?
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During RNA polymerase II transcription termination, which factors are primarily involved in interacting with its C-terminal domain?
During RNA polymerase II transcription termination, which factors are primarily involved in interacting with its C-terminal domain?
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What role does TF2E play in the transcription initiation process?
What role does TF2E play in the transcription initiation process?
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How does elongation factor TF2EB facilitate transcription?
How does elongation factor TF2EB facilitate transcription?
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Which of the following transcription factors directly interacts with RNA polymerase II to bind to the promoter?
Which of the following transcription factors directly interacts with RNA polymerase II to bind to the promoter?
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Study Notes
Eukaryotic Transcription
- Eukaryotes have three RNA polymerase enzymes: RNA polymerase I, II, and III.
- RNA polymerase II is responsible for transcribing mRNA.
- Transcription factors are proteins that help RNA polymerase II initiate transcription.
- Transcription factors are designated with the prefix "TF" followed by the number of the RNA polymerase they interact with, and then a letter indicating its function.
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TF2D is the first transcription factor to bind to the promoter.
- TF2D contains TBP, a protein that binds to the TATA box, a sequence located about 30 nucleotides upstream of the transcription start site.
- TBP bends DNA by 80 degrees, facilitating the binding of other transcription factors.
- TF2A helps stabilize TF2D binding.
- TF2B binds to TBP and the promoter region downstream of the TATA box, and recruits RNA polymerase II.
- TF2F interacts with RNA polymerase II to bind to the promoter, and assists RNA polymerase II in contacting DNA outside the promoter.
- TF2E binds to the pre-initiation complex and helps recruit TF2H.
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TF2H is a large complex with nine subunits.
- Two subunits possess ATPase activity, acting as a helicase to melt the promoter, transitioning the pre-initiation complex to an open complex.
- The remaining seven subunits have kinase activity, phosphorylating the C-terminal domain (CTD) of RNA polymerase II, triggering promoter escape and transcription elongation.
Transcription Elongation
- Elongation factors assist RNA polymerase II during elongation.
- TF2EB is a kinase protein that phosphorylates serine residues in the CTD of RNA polymerase II, stimulating elongation.
- TF2S increases the rate of transcription at regions where it slows down and prevents RNA polymerase from pausing.
mRNA Processing
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5' capping occurs during elongation.
- The terminal gamma phosphate of the first nucleotide is removed by RNA triphosphatase.
- Guanylyl transferase adds a guanine nucleotide to the 5' end, creating a 5' cap.
- Methyl transferase adds a methyl group to the guanine nucleotide.
- The 5' cap helps recruit mRNA to the ribosome for translation initiation.
Transcription Termination
- When RNA polymerase II reaches the end of a gene, its CTD interacts with CSDF (cleavage stimulation factor) and CPSF (cleavage and polyadenylation specificity factor).
- Once the end of the gene is transcribed into RNA, CPSF and CSTF are recruited to the mRNA.
- CSTF disassociates after the mRNA is cleaved.
- CPSF recruits poly(A) polymerase, which adds a poly(A) tail of about 200-250 adenine residues to the 3' end of the mRNA.
- Poly(A) binding protein binds to the poly(A) tail and prevents its degradation.
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Description
This quiz covers the key aspects of eukaryotic transcription, focusing on the role of RNA polymerase II and various transcription factors. Learn about the binding process of TF2D and its interaction with the TATA box and other transcription factors. Test your understanding of how eukaryotic transcription is initiated and regulated.
