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Antagomirs also known as anti-miRs or blockmirs are a class of chemically engineered oligonucleotides that prevent other molecules from binding to a desired site on an mRNA molecule. Antagomirs are used to silence endogenous microRNA (miR). An antagomir is a small synthetic RNA that is perfectly complementary to the specific miRNA target with either mispairing at the cleavage site of Ago2 or some sort of base modification to inhibit Ago2 cleavage. Usually, antagomirs have some sort of modification, such as 2'-methoxy groups and phosphorothioates, to make them more resistant to degradation. == Mechanism of action == Antagomirs are microRNA inhibitors that inhibit miRNAs but, because of the promiscuity of microRNAs, antagomirs could affect the regulation of many different mRNA molecules. It is unclear how antagomirization (the process by which an antagomir inhibits miRNA activity) operates, but it is believed to inhibit by irreversibly binding the miRNA. Blockmirs are designed to have a sequence that is complementary to an mRNA sequence that serves as a binding site for microRNA. Upon binding, Blockmirs sterically block microRNA from binding to the same site, which prevents the degradation of the target mRNA via RNA-induced silencing complex (RISC). If a Blockmir binds to a non-intended RNA, it will only cause an effect if it prevents binding of a microRNA or another cellular factor. This occurrence is highly unlikely, meaning off-target effects will rarely be an issue. Hence, Blockmirs enable modulation of microRNA-based gene regulation with exquisite specificity. Importantly, Blockmirs are typically agonists of their target mRNA, i.e. they increase the synthesis of the protein encoded by the target mRNA. Blockmirs bind on the 3’ end of the untranslated region (UTR) of the mRNA strand, which adequately blocks microRNA from binding, as most microRNAs do not bind to the translated region. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Antagomir」の詳細全文を読む スポンサード リンク
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