Which one among the following is an important constituent of RNA induced silencing complex in plants?
Which one among the following is an important constituent of RNA induced silencing complex in plants?
Select an option to attempt
Correct Answer: Option A
Explanation
Argonaute proteins and RISC function:RNA interference (RNAi) pathway:1. Long dsRNA or pre-miRNA is processed by DICER into short ~21–23 nt duplexes (siRNA or miRNA).2. One strand (guide strand) is loaded into the RISC (RNA-Induced Silencing Complex).3. RISC is assembled around an ARGONAUTE (AGO) protein:• AGO carries the guide RNA.• PAZ domain: anchors the 3' end of the guide RNA.• PIWI domain: contains the Slicer endonuclease activity (cleaves the target mRNA at the site complementary to positions 10-11 of the guide strand).4. RISC scans mRNAs for complementary sequences:• Perfect complement (siRNA-like): mRNA cleavage.• Imperfect complement (miRNA-like): translational repression + mRNA destabilisation.AGO2 in humans has active Slicer activity; AGO1, AGO3, AGO4 lack it.Answer: Argonaute is the core catalytic component of RISC that uses guide miRNA/siRNA to silence target mRNAs.