Question

Rna mediated interference is a post-transcriptional gene silencing mechanism. which component(s) of the rnai pathway have been implicated in the endonucleolytic cleavage of the target mrna?

a. dicer enzyme
b. the risc complex
c. the drosha complex
d. the exosome xrn1

Answer 1

The DICER enzyme and the RISC complex are involved in the endonucleolytic cleavage of the target mRNA in the RNAi pathway. The DICER cuts double-stranded RNAs into short molecules, and these are then directed by the RISC complex to complementary mRNAs, leading to their cleavage and degradation.

Step-by-step explanation:

The component(s) of the RNA interference (RNAi) pathway implicated in the endonucleolytic cleavage of the target mRNA are the DICER enzyme and the RISC complex. The DICER enzyme is an endonuclease that cleaves double-stranded RNAs (dsRNAs) into short molecules, typically around 20 nucleotides long. These siRNAs or miRNAs are then incorporated into the RISC complex, which is responsible for guiding the siRNA to bind to its complementary mRNA, leading to its cleavage and subsequent degradation if the match is perfect.

The Drosha complex is involved earlier in the miRNA processing pathway, generating precursor miRNAs (pre-miRNAs) that will be later processed by DICER, while the exosome and XRN1 are generally associated with general RNA degradation pathways rather than endonucleolytic cleavage specifically directed by the RNAi machinery. Therefore, the correct answer to the question is A. DICER enzyme and B. the RISC complex.