Single-Base Resolution Detection of Adenosine-to-Inosine RNA Editing by Endonuclease-Mediated Sequencing

RNA molecules contain diverse modifications that play crucial roles in a wide variety of biological processes. Adenosine-to-inosine (A-to-Ino) RNA editing is one of the most prevalent modifications among all types of RNA. Abnormal A-to-InoRNA editing has been demonstrated to be associated with many human diseases. Identification of A-to-Ino editing sites is indispensable to deciphering their biological roles. Herein, by employing the unique property of human endonuclease V (hEndoV), we proposed a hEndoV-mediated sequencing (hEndoV-seq) method for the single-base resolution detection of A-to-InoRNA editing sites. In this approach, the terminal 3'OH of RNA is first blocked by 3'-deoxyadenosine (3'-deoxy-A). Specific cleavage of Ino sites by hEndoV protein produces new terminal 3'OH, which can be identified by sequencing analysis, and therefore offers the site-specific detection of Ino in RNA. The principle of hEndoV-seq is straightforward and the analytical procedure is simple. No chemical reaction is involved in the sequencing library preparation. The whole procedure in hEndoV-seq is carried out under mild conditions and RNA is not prone to degradation. Taken together, the proposed hEndoV-seq method is capable of site-specific identification of A-to-Ino editing in RNA, which provides a valuable tool for elucidating the functions of A-to-Ino editing in RNA.