What are the two main types of transcription termination in bacteria?

What are the two main types of transcription termination in bacteria?

• A. Rho-dependent
• B. Rho-dependent and Rho-independent
• C. Intrinsic termination
• D. Protein-dependent termination

Answer: (B)

In bacteria, transcription termination happens mainly by two mechanisms: Rho-dependent termination and intrinsic termination, also called Rho-independent termination. Rho-dependent termination uses the Rho factor, a helicase that binds to the growing RNA at specific rut sites. As RNA polymerase pauses, Rho catches up and, using ATP energy, separates the RNA from the DNA template and dismantles the transcription complex to release the RNA transcript. Intrinsic (Rho-independent) termination relies on the RNA sequence itself. It forms a GC-rich hairpin structure followed by a string of uracils in the transcript. The hairpin causes RNA polymerase to pause, and the weak A–U pairing in the RNA-DNA hybrid after the hairpin makes dissociation favorable, leading to termination without any additional factors. Therefore, the two main types are Rho-dependent termination and intrinsic (Rho-independent) termination.

In bacteria, transcription termination happens mainly by two mechanisms: Rho-dependent termination and intrinsic termination, also called Rho-independent termination.

Rho-dependent termination uses the Rho factor, a helicase that binds to the growing RNA at specific rut sites. As RNA polymerase pauses, Rho catches up and, using ATP energy, separates the RNA from the DNA template and dismantles the transcription complex to release the RNA transcript.

Intrinsic (Rho-independent) termination relies on the RNA sequence itself. It forms a GC-rich hairpin structure followed by a string of uracils in the transcript. The hairpin causes RNA polymerase to pause, and the weak A–U pairing in the RNA-DNA hybrid after the hairpin makes dissociation favorable, leading to termination without any additional factors.

Therefore, the two main types are Rho-dependent termination and intrinsic (Rho-independent) termination.