Methylation status of intracellular dengue type 2 40 S RNA

Cleaves, Graham R.; Dubin, Donald T.

doi:10.1016/0042-6822(79)90181-8

Cited by 125 publications

(85 citation statements)

References 29 publications

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“…The purified genome RNA is infectious and is designated as "plus"-stranded. The RNA contains a type 1 5'-terminal M 7 GpppAmp Nl cap structure (Cleaves and Dubin, 1979;Wengler et a1., 1978).…”

Section: Genome Rnamentioning

confidence: 99%

Replication of Flaviviruses

Brinton

1986

The Togaviridae and Flaviviridae

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Section: Genome Rnamentioning

confidence: 99%

Replication of Flaviviruses

Brinton

1986

The Togaviridae and Flaviviridae

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“…Among the four enzymes required for flavivirus m 7 GpppAm-cap formation, the RNA triphosphatase has been mapped to NS3 (12,13). Recent studies suggest that the N-terminal methyltransferase (MTase) domain of NS5 has a guanylyltransferase activity, transferring the GMP moiety of GTP to the 5Ј end of ppA-RNA, resulting in GpppA-RNA (25,26).…”

mentioning

confidence: 99%

“…mRNA) polarity. A type I cap (see details below) is present at the 5Ј end, followed by the conserved dinucleotide sequence 5Ј-AG-3Ј (m 7 GpppAmG) (7). The 3Ј end of the genome terminates with 5Ј-CU OH -3Ј rather than with a poly(A) tract (8).…”

mentioning

confidence: 99%

Structural and Functional Analyses of a Conserved Hydrophobic Pocket of Flavivirus Methyltransferase

Dong

Liu

Zou

et al. 2010

Journal of Biological Chemistry

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The flavivirus methyltransferase (MTase) sequentially methylates the N7 and 2-O positions of the viral RNA cap (GpppA-RNA 3 m 7 GpppA-RNA 3 m 7 GpppAm-RNA), using S-adenosyl-L-methionine (AdoMet) as a methyl donor. We report here that sinefungin (SIN), an AdoMet analog, inhibits several flaviviruses through suppression of viral MTase. The crystal structure of West Nile virus MTase in complex with SIN inhibitor at 2.0-Å resolution revealed a flavivirus-conserved hydrophobic pocket located next to the AdoMet-binding site. The pocket is functionally critical in the viral replication and cap methylations. In addition, the N7 methylation efficiency was found to correlate with the viral replication ability. Thus, SIN analogs with modifications that interact with the hydrophobic pocket are potential specific inhibitors of flavivirus MTase.The genus Flavivirus in the family Flaviviridae is composed of more than 70 viruses (1). Many flaviviruses are arthropodborne and cause significant human disease. The four serotypes of Dengue virus (DENV), 5 yellow fever virus (YFV), West Nile virus (WNV), Japanese encephalitis virus, and tick-borne encephalitis virus, are categorized as global emerging pathogens and are also National Institutes of Health NIAID Priority Pathogens (2). The World Health Organization has estimated annual human cases of more than 50 million, 200,000, and 50,000 for DENV (3), YFV (4), and Japanese encephalitis virus (5), respectively. Approximately 2.5 billion people are at risk of DENV infection (3). Since 1999, WNV has spread rapidly throughout the Western Hemisphere (6). Vaccines for humans are currently available only for YFV, Japanese encephalitis virus, and tick-borne encephalitis virus (2). No clinically approved antiviral therapy is available for treatment of flavivirus infections. Therefore, the development of vaccines and antiviral agents for prevention and treatment of flavivirus infections is a clear public health priority (6).The flavivirus genomic RNA is single-stranded and of positive (i.e. mRNA) polarity. A type I cap (see details below) is present at the 5Ј end, followed by the conserved dinucleotide sequence 5Ј-AG-3Ј (m 7 GpppAmG) (7). The 3Ј end of the genome terminates with 5Ј-CU OH -3Ј rather than with a poly(A) tract (8). The viral genome is ϳ11 kb in length, consisting of a 5Ј UTR, a single long open reading frame (ORF), and a 3Ј UTR (9). The single ORF encodes a polyprotein that is co-and posttranslationally processed by viral and cellular proteases into three structural proteins (capsid (C), premembrane (prM), or membrane (M), and envelope (E)), and seven nonstructural proteins (NS1, NS2a, NS2b, NS3, NS4a, NS4b, and NS5) (10). The nonstructural proteins are assumed to be involved primarily in the replication of viral RNA, as components of a replicase complex. Among the NS proteins, NS3 is a multifunctional protein with activities of a serine protease, an RNA triphosphatase, a nucleoside triphosphatase, and a helicase (11-13); NS5 has the functions of an RNA-dependent RNA polymerase...

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“…The genomic RNA contains a 5= untranslated region (UTR) with a type I cap (m 7 GpppAm) (2), a single open-reading frame (ORF), and a 3= UTR. The ORF encodes a long polyprotein, which is co-and posttranslationally processed by a combination of viral and cellular proteases into three structural proteins (capsid [C], premembrane [prM], and envelope [E]) and seven nonstructural proteins (NS1, NS2A, NS2B, NS3, NS4A, NS4B, and NS5).…”

mentioning

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Membrane Topology and Function of Dengue Virus NS2A Protein

Xie

Gayen

Kang

et al. 2013

J Virol

170

188

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Flavivirus nonstructural protein 2A (NS2A) is a component of the viral replication complex that functions in virion assembly and antagonizes the host immune response. Although flavivirus NS2A is known to associate with the endoplasmic reticulum (ER) membrane, the detailed topology of this protein has not been determined. Here we report the first topology model of flavivirus NS2A on the ER membrane. Using dengue virus (DENV) NS2A as a model, we show that (i) the N-terminal 68 amino acids are located in the ER lumen, with one segment (amino acids 30 to 52) that interacts with ER membrane without traversing the lipid bilayer; (ii) amino acids 69 to 209 form five transmembrane segments, each of which integrally spans the ER membrane; and (iii) the C-terminal tail (amino acids 210 to 218) is located in the cytosol. Nuclear magnetic resonance (NMR) structural analysis showed that the first membrane-spanning segment (amino acids 69 to 93) consists of two helices separated by a "helix breaker." The helix breaker is formed by amino acid P85 and one positively charged residue, R84. Functional analysis using replicon and genome-length RNAs of DENV-2 indicates that P85 is not important for viral replication. However, when R84 was replaced with E, the mutation attenuated both viral RNA synthesis and virus production. Remarkably, an R84A mutation did not affect viral RNA synthesis but blocked intracellular formation of infectious virions. Collectively, the mutagenesis results demonstrate that NS2A functions in both DENV RNA synthesis and virion assembly/maturation. The topology model of DENV NS2A provides a good starting point for studying how flavivirus NS2A modulates viral replication and evasion of host immune response.

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Methylation status of intracellular dengue type 2 40 S RNA

Cited by 125 publications

References 29 publications

Replication of Flaviviruses

Replication of Flaviviruses

Structural and Functional Analyses of a Conserved Hydrophobic Pocket of Flavivirus Methyltransferase

Membrane Topology and Function of Dengue Virus NS2A Protein

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