miRNAs are major regulators of gene expression. In an experiment, it was observed that gene 'X' is a direct target of miRNA 'A'. Upon overexpression…
miRNAs are major regulators of gene expression. In an experiment, it was observed that gene 'X' is a direct target of miRNA 'A'. Upon overexpression of miRNA 'A' in Arabidopsis thaliana:
Select an option to attempt
Correct Answer: Option D
Explanation
Plant miRNA functions: mRNA cleavage and translational inhibition:Plant miRNAs act through two main mechanisms:1. Target mRNA cleavage: Plant miRNAs generally have near-perfect complementarity to their targets → RISC-mediated endonucleolytic cleavage of the mRNA → reduced mRNA levels.2. Translational repression: Less dominant in plants compared to animals, but can occur with imperfect base-pairing.Consequence of overexpressing a miRNA targeting gene X:• Overexpression → MORE miRNA → MORE RISC-miRNA complexes targeting gene X mRNA.• Increased cleavage of gene X mRNA → REDUCED mRNA abundance.• Reduced protein translation from remaining mRNA.• Net result: BOTH mRNA and protein levels of gene X decrease.Answer: Overexpression of miRNA 'A' reduces both mRNA levels (via cleavage) and protein levels of target gene X.