Barral K, Sallamand C, Petzold C, Coutard B, Collet A, Thillier Y, Zimmermann J, Vasseur JJ, Canard B, Rohayem J, Debart F, Decroly E. Development of specific dengue virus 2'-O- and N7-methyltransferase assays for antiviral drug screening.
Antiviral Res 2013;
99:292-300. [PMID:
23769894 DOI:
10.1016/j.antiviral.2013.06.001]
[Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Revised: 05/31/2013] [Accepted: 06/03/2013] [Indexed: 12/16/2022]
Abstract
Dengue virus (DENV) protein NS5 carries two mRNA cap methyltransferase (MTase) activities involved in the synthesis of a cap structure, (7Me)GpppA(2'OMe)-RNA, at the 5'-end of the viral mRNA. The methylation of the cap guanine at its N7-position (N7-MTase, (7Me)GpppA-RNA) is essential for viral replication. The development of high throughput methods to identify specific inhibitors of N7-MTase is hampered by technical limitations in the large scale synthesis of long capped RNAs. In this work, we describe an efficient method to generate such capped RNA, GpppA(2'OMe)-RNA₇₄, by ligation of two RNA fragments. Then, we use GpppA(2'OMe)-RNA₇₄ as a substrate to assess DENV N7-MTase activity and to develop a robust and specific activity assay. We applied the same ligation procedure to generate (7Me)GpppA-RNA₇₄ in order to characterize the DENV 2'-O-MTase activity specifically on long capped RNA. We next compared the N7- and 2'-O-MTase inhibition effect of 18 molecules, previously proposed to affect MTase activities. These experiments allow the validation of a rapid and sensitive method easily adaptable for high-throughput inhibitor screening in anti-flaviviral drug development.
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