What is the primary role of siRNA in gene regulation?

What is the primary role of siRNA in gene regulation?

• A. Catalyze transcription initiation
• B. Stabilize mRNA
• C. Mediate RNA interference to silence gene expression
• D. Catalyze protein folding

Answer: (C)

Small interfering RNA (siRNA) functions to silence gene expression through RNA interference. It starts as a long double-stranded RNA that Dicer processes into short siRNA duplexes. One strand, the guide strand, loads into the RNA-induced silencing complex (RISC), which uses the siRNA sequence to find a complementary messenger RNA. When there is strong base pairing, Argonaute within RISC cleaves the target mRNA, leading to its degradation and a decrease in the corresponding protein. Sometimes imperfect pairing can repress translation or promote mRNA decay, but the overall effect is reduced gene expression. This post-transcriptional silencing is the hallmark of siRNA’s role, unlike initiation of transcription, mRNA stabilization, or assisting in protein folding.

Small interfering RNA (siRNA) functions to silence gene expression through RNA interference. It starts as a long double-stranded RNA that Dicer processes into short siRNA duplexes. One strand, the guide strand, loads into the RNA-induced silencing complex (RISC), which uses the siRNA sequence to find a complementary messenger RNA. When there is strong base pairing, Argonaute within RISC cleaves the target mRNA, leading to its degradation and a decrease in the corresponding protein. Sometimes imperfect pairing can repress translation or promote mRNA decay, but the overall effect is reduced gene expression. This post-transcriptional silencing is the hallmark of siRNA’s role, unlike initiation of transcription, mRNA stabilization, or assisting in protein folding.