In RNAi screens, siRNAs are incubated with cells in culture to assess functional consequences of the targeted gene. Which statement regarding siRNA and its action is true?
A) The siRNA is homologous to and binds intronic gene sequences, preventing appropriate RNA splicing.
B) The siRNA is homologous to and binds promoter sequences in the gene, preventing expression of the gene.
C) The siRNA is homologous to and binds exonic gene sequences, giving rise to a truncated nonfunctional protein.
D) The siRNA is homologous to and binds the mRNA, leading to degradation of the mRNA.

Question

Quizplus · Accepted Answer

siRNA is designed to be homologous to the mRNA of the targeted gene. Once it binds to the mRNA, it recruits the RNA-induced silencing complex (RISC) and triggers mRNA cleavage or degradation. This results in decreased levels of the targeted gene product, which can then be assessed for functional consequences in the RNAi screen.

In RNAi Screens, SiRNAs Are Incubated with Cells in Culture