Answer to Question #91858 in Microbiology for Ayesha Khan

Question

Why are miRNA binding sites located in the 3' UTR and not in the 5' UTR? What would happen if we move it from 3' UTR to 5' UTR ?

Answer 1

miRNA sites are mainly located in the 3' UTR of mRNA due to the nature of the interaction between two seqeunces. In detail, the 5'UTR conserved region (8 nucleotide seed ) interacts with 3' UTR region of mRNA forming a complementary pair which initiates inhibition of translation or mRNA degradation. If binding site was at 5' UTR then the pair would be formed between less conserved 3'UTR of miRNA and 5'UTR of mRNA. Absence of complementary pairing can have a significant impact on the biological function of miRNA.