Phenotypic analysis of mutations at residue 146 provides insights into the relationship between NS5A hyperphosphorylation and hepatitis C virus genome replication

Goonawardane, N; Yin, C; Harris, M

Journal article

Phenotypic analysis of mutations at residue 146 provides insights into the relationship between NS5A hyperphosphorylation and hepatitis C virus genome replication

Abstract:: The hepatitis C virus genotype 2a isolate, JFH-1, exhibits much more efficient genome replication than other isolates. Although basic replication mechanisms must be conserved, this raises the question of whether the regulation of replication might exhibit isolate- and/or genotype-specific characteristics. Exemplifying this, the phenotype of NS5A hyperphosphorylation is genotype-dependent; in genotype 1b a loss of hyperphosphorylation correlates with an enhancement of replication. In contrast, the replication of JFH-1 is not regulated by hyperphosphorylation. We previously identified a novel phosphorylation site in JFH-1 NS5A: S146. A phosphomimetic substitution (S146D) had no effect on replication but correlated with a loss of hyperphosphorylation. In genotype 1b, residue 146 is alanine and we therefore investigated whether the substitution of A146 with a phosphorylatable (S), or phosphomimetic, residue would recapitulate the JFH-1 phenotype, decoupling hyperphosphorylation from replication. This was not the case, as A146D exhibited both a loss of hyperphosphorylation and a reduction in replication, accompanied by a perinuclear restriction of replication complexes, reductions in lipid droplet and PI4P lipid accumulation, and a disruption of NS5A dimerization. In contrast, the S232I culture-adaptive mutation in the low-complexity sequence I (LCSI) also exhibited a loss of hyperphosphorylation, but was associated with an increase in replication. Taken together, these data imply that hyperphosphorylation does not directly regulate replication. In contrast, the loss of hyperphosphorylation is a consequence of perturbing genome replication and NS5A function. Furthermore, we show that mutations in either domain I or LCSI of NS5A can disrupt hyperphosphorylation, demonstrating that multiple parameters influence the phosphorylation status of NS5A

Publication status:: Published

Peer review status:: Peer reviewed

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APA Style

Goonawardane, N., Yin, C., & Harris, M. (2019). Phenotypic analysis of mutations at residue 146 provides insights into the relationship between NS5A hyperphosphorylation and hepatitis C virus genome replication. Journal of General Virology, 101(3), 252–264.

MLA Style

Goonawardane, N, et al. “Phenotypic Analysis of Mutations at Residue 146 Provides Insights into the Relationship between NS5A Hyperphosphorylation and Hepatitis C Virus Genome Replication.” Journal of General Virology, vol. 101, no. 3, 2019, pp. 252–64.

Chicago Style

Goonawardane, N, C Yin, and M Harris. 2019. “Phenotypic Analysis of Mutations at Residue 146 Provides Insights into the Relationship between NS5A Hyperphosphorylation and Hepatitis C Virus Genome Replication.” Journal of General Virology 101 (3): 252–64.
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