Poster abstracts

Poster number 56 submitted by Elizabeth DeLaney

RNA recognition by the pattern recognition receptor RIG-I involves oligomerization and ATPase activation by blunt duplex ends

Elizabeth DeLaney (Center for RNA Molecular Biology, Case Western Reserve University), Zhenrui Li (Center for RNA Molecular Biology, Case Western Reserve University), Andrea Putnam (Center for RNA Molecular Biology, Case Western Reserve University), Eckhard Jankowsky (Center for RNA Molecular Biology, Case Western Reserve University)

Abstract:
Recognition of viral RNA by mammalian cells is critical for the activation of the innate immune system. Viral RNA is recognized by several pathogen recognition receptors, including RIG-I, an ATP-dependent RNA helicase. RIG-I binds to the termini of RNA duplexes, but it is not clear which exact conformational elements in the RNA trigger activation of RIG-I. To address this question, we examined RNA binding, ATPase activity, and oligomerization of RIG-I for a series of defined model substrates in vitro. We find that RIG-I forms oligomers on duplexes with more than 16 bp. While RIG-I binds to RNA duplexes with and without blunt ends, ATPase activity is only activated by RNA duplexes containing a blunt end. Finally, we observe that dissociation of RIG-I from RNA is enhanced by ATP. Collectively, our data indicate that the length of the duplex and exact blunt ends of RNA duplexes are critical for RIG-I activation. Our observations further indicate that RIG-I forms oligomers on duplex RNAs, but only the terminal protomer hydrolyzes ATP.

Keywords: RIG-I, ATPase, oligomerization