1. Eukaryotic transcription initiation begins at the TATA site approximately 30 bp upstream of the transcription start site. One subunit of TFIID (Transcription Factor II D) binds at the TATA site. What is this subunit? 2. This initial binding at the TATA site is specific and coincides with the binding of the entire TFIID complex. This results in a massive change of shape to the DNA helix of the promoter region. After TFIID binding and this shape change, another GTF(General Transcription Factor) can bind. What is this next GTF? 3. Next, which GTF binds to a DNA sequence in the promoter region and to the TFIID-promoter complex before the binding of the RNA Pol II-TFIIF complex? 4. Describe how would you redraw Figure 13-16 to reflect the change in the dsDNA helical shape due to the initial binding to the TATA site? 5. What other interactions, required for specific in vivo transcription initiation, would be made easier by the shape change caused by TATA site binding of the TFIID subunit in question 1? (Use Figure 13-19 as a model) **Figure 13-16: Transcription Initiation by RNA Polymerase II**This diagram illustrates the stepwise assembly of the RNA Pol II preinitiation complex at the promoter, as well as subsequent steps leading to transcription initiation.1. **Formation of the Initial Complex:** - The process begins with TFIID binding to the TATA box. TFIID contains TBP (TATA-binding protein), which recognizes and binds the TATA box in the promoter region of DNA.2. **Recruitment of TFIIB:** - TFIIB is recruited to the complex, stabilizing the interaction and providing a platform for subsequent factors to join.3. **Addition of TFIIF and RNA Polymerase II:** - TFIIF, along with RNA Polymerase II, is recruited to the complex. RNA Polymerase II contains a tail with multiple repeats of the heptapeptide sequence: Tyr-Ser-Pro-Thr-Ser-Pro-Ser.4. **Inclusion of TFIIE and TFIIH:** - TFIIE and TFIIH are subsequently incorporated into the complex. TFIIH plays a crucial role in DNA melting and promoter escape, enabling the transition from a closed preinitiation complex to an open complex.5. **Preinitiation Complex to Open Complex:** - Once assembled, the complex transitions from preinitiation to open complex form, with DNA strands partially unwound (DNA melting).6. **Initiation of Transcription:** - Using ATP, the RNA Pol II complex undergoes structural changes associated with promoter escape, leading to the initiation of RNA synthesis. This involves phosphorylation of the Pol II tail, allowing it to leave the preinitiation complex.Overall, this process outlines the critical steps leading to the initiation of RNA synthesis and the role of various general transcription factors in facilitating the proper assembly and function of the RNA Pol II machinery. **Figure 13-19: Assembly of the Pre-Initiation Complex**This diagram illustrates the assembly of the pre-initiation complex, which forms in the presence of various components including the Mediator complex, nucleosome modifiers and remodelers, and transcriptional activators. The process depicted involves several key elements:1. **Activator**: A protein that helps initiate the process by binding to specific DNA regions.2. **Mediator Complex**: A large protein complex that bridges the interaction between activators and RNA polymerase II.3. **Chromatin Remodeler**: Protein machinery that alters chromatin structure, making the DNA more accessible for transcription.4. **HAT (Histone Acetyltransferase)**: Enzyme involved in modifying histones, which aids in loosening the DNA structure.5. **RNA Polymerase II**: The enzyme responsible for transcribing DNA into messenger RNA.The gene is indicated by a looping structure of DNA where these components come together. Transcriptional activators, positioned near the gene, play a critical role in recruiting nucleosome-modifying and remodeling complexes along with the Mediator complex. These combined actions are crucial for forming the complete pre-initiation complex, facilitating the initiation of transcription.

This questions are about transcription.

1. Eukaryotic transcription initiation begins at the TATA site approximately 30 bp upstream of the transcription start site. One subunit of TFIID (Transcription Factor II D) binds at the TATA site. What is this subunit? 2. This initial binding at the TATA site is specific and coincides with the binding of the entire TFIID complex. This results in a massive change of shape to the DNA helix of the promoter region. After TFIID binding and this shape change, another GTF(General Transcription Factor) can bind. What is this next GTF? 3. Next, which GTF binds to a DNA sequence in the promoter region and to the TFIID-promoter complex before the binding of the RNA Pol II-TFIIF complex? 4. Describe how would you redraw Figure 13-16 to reflect the change in the dsDNA helical shape due to the initial binding to the TATA site? 5. What other interactions, required for specific in vivo transcription initiation, would be made easier by the shape change caused by TATA site binding of the TFIID subunit in question 1? (Use Figure 13-19 as a model)

11th Edition

ISBN:9780134580999

Author:Elaine N. Marieb, Katja N. Hoehn

Publisher:Elaine N. Marieb, Katja N. Hoehn

Chapter1: The Human Body: An Orientation

Section: Chapter Questions

Problem 1RQ: The correct sequence of levels forming the structural hierarchy is A. (a) organ, organ system,...