RNA interference
How does a small interfering RNA (siRNA) reduce expression of a target gene?
Answer B: explanation for every choice
A
Promoter methylation is a separate mechanism of silencing.
B
Correct. The siRNA strand loaded into RISC base-pairs with its target mRNA, which is cleaved and degraded.
C
siRNA targets mRNA after transcription, not DNA.
D
siRNA does not inhibit ribosomes in general.
TakeawayRNAi silences genes after transcription by destroying mRNA.
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Reviewed 2026-11-05 by a medical student. Spot an error? Report it with question ID bb132.