Podcast
Questions and Answers
What is the characteristic feature of a Rho-independent terminator?
What is the characteristic feature of a Rho-independent terminator?
What is a key protein involved in Rho-dependent termination?
What is a key protein involved in Rho-dependent termination?
How many bases are typically found after the loop in a Rho-independent terminator?
How many bases are typically found after the loop in a Rho-independent terminator?
What is the approximate size of the Rho factor protein?
What is the approximate size of the Rho factor protein?
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Which activity is associated with the Rho factor in facilitating Rho-dependent termination?
Which activity is associated with the Rho factor in facilitating Rho-dependent termination?
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What happens to chain elongation when RNA polymerase encounters a transcription-termination signal?
What happens to chain elongation when RNA polymerase encounters a transcription-termination signal?
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Study Notes
Rho-Independent Termination
- Characterized by a G-C rich stem and a 7-9 base U-run after the loop
- U-DNA pairing is very weak, allowing for dissociation
Rho-Dependent Termination
The Rho Factor
- A 46-kD protein that is active as a hexamer
- Binds to specific sequences on RNA (50-90 bp)
- Has helicase activity, separating RNA-DNA
How it Works
- Binds to RNA tail and moves along the transcript until it catches up to the polymerase (Hot Pursuit Model)
- Causes RNA-DNA separation through its helicase activity, leading to termination
Key Points of RNA Synthesis
- Occurs in three stages: initiation, elongation, and termination
- RNA polymerases are complex multimeric proteins that catalyze transcription
- RNA chain elongation occurs within locally unwound segments of DNA
- Transcription-termination signals halt RNA synthesis
- Transcription, translation, and mRNA degradation often occur simultaneously in prokaryotes
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Description
Learn about rho-independent and rho-dependent termination mechanisms in transcription, including the role of the rho factor and its helicase activity.
