Selection and Partial Characterization of Dengue 2 Virus Mutants That Induce Fusion at Elevated pH

Infectious clone construction of dengue virus type 2, strain Jamaican 1409, and characterization of a conditional E6 mutation

“…While our P-0 C6/36-generated 1409ic had no unexpected sequence variations, we did find that C6/36 P-3 1409ic virus had a nucleotide change in the genome that produced an AsnRHis mutation at E-155 that resulted in the loss of a conserved glycosylation site. The loss of this glycosylation site in dengue viruses due to repeated passage in C6/36 cells has also been described by others (Guirakhoo et al, 1993;Lee et al, 1997). Moreover, these data raise questions about the role and impact of host-cell defences to viral infection (e.g.…”

“…As our 1409hp stock had been cultured repeatedly in mosquito cells (>25 times), celladapted selection may have yielded the observed mutation. Previous work has found that repeated passage of DENV-2 (strain Jamaica) in C6/36 cells also resulted in an IleRMet variation at E6 (Guirakhoo et al, 1993). These authors noted that the DENV-2 with E6-Met was coded in the genome of a fusion-mutant strain of DENV-2, although a direct link between a specific amino acid residue and the fusion phenotype was not established.…”

“…The DENV-2 genome is a single-stranded, positive-sense RNA molecule of approximately 10 700 nt that contains a type I 59-cap structure, but lacks a 39 poly(A) tail. The genome is translated directly as a single polyprotein containing the three structural genes (NH 2 -CapsidprM-Envelope) fused to the seven non-structural genes (NS1-NS2A-NS2B-NS3-NS4A-NS4B-NS5-COOH) that is processed co-and post-translationally (Chambers et al, 1990).Molecular analysis of the envelope gene from DENV-2 field isolates originally identified five major DENV-2 genotypes: Caribbean (American), South Pacific, Middle East and Indonesia, Vietnam and Thailand (Asian), and West African (Lewis et al, 1993;Rico-Hesse, 1990;Rico-Hesse et al, 1997;Wang et al, 2000). Additional analysis of more DENV-2 samples has revealed a total of six DENV-2 genotypes: American, American/Asian, Asian I, Asian II, Sylvatic and Cosmopolitan (Twiddy et al, 2002).…”

“…Molecular analysis of the envelope gene from DENV-2 field isolates originally identified five major DENV-2 genotypes: Caribbean (American), South Pacific, Middle East and Indonesia, Vietnam and Thailand (Asian), and West African (Lewis et al, 1993;Rico-Hesse, 1990;Rico-Hesse et al, 1997;Wang et al, 2000). Additional analysis of more DENV-2 samples has revealed a total of six DENV-2 genotypes: American, American/Asian, Asian I, Asian II, Sylvatic and Cosmopolitan (Twiddy et al, 2002).…”

Post-translational regulation and modifications of flavivirus structural proteins

“…Trans-membrane domains and membrane-associated helices are represented as cylinders. pH environments and the infectivity of mature virus particles (Beasley et al, 2005; Goto et al, 2005;Guirakhoo et al, 1993;Hanna et al, 2005;Lee et al, 1997Lee et al, , 2010Li et al, 2006;Mondotte et al, 2007;Scherret et al, 2001). Exploitation of these post-translational control measures has facilitated the continuing development of novel vaccines and therapeutics for use against flavivirus infections (Goto et al, 2005; Keelapang et al, 2013;Ohtaki et al, 2010;Pang et al, 2014;Roby et al, 2011Roby et al, , 2013Roby et al, , 2014Zhang et al, 2011).…”