In eukaryotes, termination involves which signal and processing?

In eukaryotes, termination involves which signal and processing?

• A. DNA terminator sequence
• B. Polyadenylation signal AAUAA with cleavage
• C. Rho-dependent termination
• D. No termination

Answer: (B)

In eukaryotes, transcription termination is governed by the processing of the newly transcribed RNA at its 3' end. The key signal is the polyadenylation signal, AAUAAA, which marks the site where the pre-mRNA will be cleaved. After cleavage, poly(A) polymerase adds the poly(A) tail. This 3' end processing is what facilitates termination of transcription and yields a mature mRNA ready for export and translation. This is different from the other options: a DNA terminator sequence works in many bacteria but not in eukaryotic transcription; rho-dependent termination is a bacterial mechanism; and saying there is no termination would be incorrect because transcription ends through this processing-linked mechanism.

In eukaryotes, transcription termination is governed by the processing of the newly transcribed RNA at its 3' end. The key signal is the polyadenylation signal, AAUAAA, which marks the site where the pre-mRNA will be cleaved. After cleavage, poly(A) polymerase adds the poly(A) tail. This 3' end processing is what facilitates termination of transcription and yields a mature mRNA ready for export and translation.

This is different from the other options: a DNA terminator sequence works in many bacteria but not in eukaryotic transcription; rho-dependent termination is a bacterial mechanism; and saying there is no termination would be incorrect because transcription ends through this processing-linked mechanism.