Length-dependent recognition of double-stranded ribonucleic acids by retinoic acid–inducible gene-I and melanoma differentiation–associated gene 5

Abstract

The ribonucleic acid (RNA) helicases retinoic acid-inducible gene-I (RIG-I) and melanoma differentiation–associated gene 5 (MDA5) recognize distinct viral and synthetic RNAs, leading to the production of interferons. Although 5′-triphosphate single-stranded RNA is a RIG-I ligand, the role of RIG-I and MDA5 in double-stranded (ds) RNA recognition remains to be characterized. In this study, we show that the length of dsRNA is important for differential recognition by RIG-I and MDA5. The MDA5 ligand, polyinosinic-polycytidylic acid, was converted to a RIG-I ligand after shortening of the dsRNA length. In addition, viral dsRNAs differentially activated RIG-I and MDA5, depending on their length. Vesicular stomatitis virus infection generated dsRNA, which is responsible for RIG-I–mediated recognition. Collectively, RIG-I detects dsRNAs without a 5′-triphosphate end, and RIG-I and MDA5 selectively recognize short and long dsRNAs, respectively.

RNA helicase encoded by melanoma differentiation–associated gene 5 is a major autoantigen in patients with clinically amyopathic dermatomyositis: Association with rapidly progressive interstitial lung disease

“…MDA-5 is a member of the retinoic acidinducible gene I (RIG-I) family of RNA helicases, which also includes RIG-I and LGP-2. Recombinant MDA-5, recombinant RIG-I (rRIG-I), and recombinant LGP-2 (rLGP-2) were produced and purified as FLAG fusion proteins using a baculovirus expression system, as described previously (17,18). The individual RIG-I family proteins were used in immunoblots probed with a mouse anti-FLAG monoclonal antibody (clone M2; Sigma-Aldrich, St. Louis, MO), anti-CADM-140 antibody-positive sera, or healthy control sera.…”

Fish MAVS is involved in RLR pathway-mediated IFN response

“…In general, RIG-I preferentially binds to a short, uncapped 5 0 -trihosphorylated (5 0 -ppp) ssRNA juxtaposed to a short region of dsRNA [4,5], whereas MDA5 recognizes the internal duplex structure of dsRNA [6]. However, both are initially characterized as dsRNA-binding proteins that respond to poly (I:C), a synthetic form of dsRNA and actually, they prefer to different-sized poly (I:C) [7,8]. Following recognition of such ligands, RIG-I and MDA5 are activated and interact with a mitochondrial antiviral signaling protein (MAVS, also known as IPS-1/ VISA/Cardif), to transit antiviral signaling to downstream signaling molecules (such as TBK1 and IRF3/7) and finally orchestrate the IFN antiviral response [2,3,9].…”

Higher antiviral response of RIG-I through enhancing RIG-I/MAVS-mediated signaling by its long insertion variant in zebrafish

“…. Kato et al (2008) showed that the length of dsRNA is also important for the recognition of RIG-I, and RIG-I selectively recognizes short dsRNA, whereas MDA5 prefers long dsRNA [13]. Recently, it is reported that mammalian RIG-I functions in the recognition of a variety of viruses, ranging from positive/negative-stranded ssRNA viruses to dsRNA viruses [32e34].…”