Which statement best describes how RNA interference regulates gene expression?

Which statement best describes how RNA interference regulates gene expression?

• A. It increases transcription by opening chromatin.
• B. It changes DNA sequence at a target locus.
• C. It promotes mRNA splicing changes.
• D. It uses small interfering RNA or microRNA to silence gene expression by degrading mRNA or blocking translation.

Answer: (D)

RNA interference works by using small RNA guides to silence gene expression after transcription. Small interfering RNA (siRNA) or microRNA (miRNA) are loaded into a silencing complex that pairs with a target mRNA based on sequence complementarity. If the pairing is nearly perfect, the Argonaute enzyme within the complex cuts the mRNA, leading to its degradation. If pairing is imperfect, the complex can block translation and promote mRNA decay, reducing the protein produced from that transcript. This is a post-transcriptional control mechanism, affecting mRNA stability and translation rather than changing the DNA sequence or altering chromatin to boost transcription. So the statement that RNA interference uses siRNA or miRNA to silence gene expression by degrading mRNA or blocking translation best captures how it regulates gene expression.

RNA interference works by using small RNA guides to silence gene expression after transcription. Small interfering RNA (siRNA) or microRNA (miRNA) are loaded into a silencing complex that pairs with a target mRNA based on sequence complementarity. If the pairing is nearly perfect, the Argonaute enzyme within the complex cuts the mRNA, leading to its degradation. If pairing is imperfect, the complex can block translation and promote mRNA decay, reducing the protein produced from that transcript. This is a post-transcriptional control mechanism, affecting mRNA stability and translation rather than changing the DNA sequence or altering chromatin to boost transcription. So the statement that RNA interference uses siRNA or miRNA to silence gene expression by degrading mRNA or blocking translation best captures how it regulates gene expression.