An miRNA has the sequence 5′-GAUCGCAUUCAG-3′.Which motif on mRNA would most likely be a target of this miRNA?
A) 5′-GAUCGCAUUCAG-3′
B) 5′-CUAGCGUAAGUC-3′
C) 5′-CTAGCGTAAGTC-3′
D) 3′-CUAGCGUAAGUC-5′
E) 3′-GAUCGCAUUCAG-5′

Question

Quizplus · Accepted Answer

The miRNA sequence is read from 5' to 3', but it binds the target mRNA in an antiparallel manner, meaning it binds to the complementary sequence on the target mRNA from 3' to 5'. Therefore, to find the mRNA sequence that the miRNA targets, we need to find the complementary sequence to the miRNA sequence by reading it backward from 3' to 5'. The complementary sequence to the miRNA sequence is 5′-GAUGCGAUCUAG-3′. Among the answer choices, only D has a sequence that is complementary to the miRNA sequence. This sequence is located on the 3' untranslated region (UTR) of the mRNA, which is a common location for miRNA to bind and regulate mRNA expression.

An MiRNA Has the Sequence 5′-GAUCGCAUUCAG-3′