Accurate interpretation of inosines in RNAs: recognized as G is more than basepairing with C

Adenosine-to-inosine (A-to-I) mRNA editing epigenetically mimics A-to-G mutations. While literatures usually state "inosines are recognized as guanosines," sometimes we also see expressions like "inosines basepair with cytosines." In this article, I stress that the two expressions are not equivalent at all for the following reasons. (1) inosines are recognized as guanosines only when located in mRNAs, not tRNAs; (2) even when being recognized as guanosines, inosines can basepair with cytosine and uracil; (3) when inosine pairs with cytosine, the basepairing efficiency differs from G:C pairing. Therefore, we should be cautious when introducing A-to-I RNA editing. "inosines basepair with cytosines" is an inaccurate or incomplete interpretation and should be corrected as "inosines in mRNAs are recognized as guanosines."