Molecular characterization of the RNA-protein complex directing -2/-1 programmed ribosomal frameshifting during arterivirus replicase expression.
J Biol Chem
; 295(52): 17904-17921, 2020 12 25.
Article
em En
| MEDLINE
| ID: mdl-33127640
ABSTRACT
Programmed ribosomal frameshifting (PRF) is a mechanism used by arteriviruses like porcine reproductive and respiratory syndrome virus (PRRSV) to generate multiple proteins from overlapping reading frames within its RNA genome. PRRSV employs -1 PRF directed by RNA secondary and tertiary structures within its viral genome (canonical PRF), as well as a noncanonical -1 and -2 PRF that are stimulated by the interactions of PRRSV nonstructural protein 1ß (nsp1ß) and host protein poly(C)-binding protein (PCBP) 1 or 2 with the viral genome. Together, nsp1ß and one of the PCBPs act as transactivators that bind a C-rich motif near the shift site to stimulate -1 and -2 PRF, thereby enabling the ribosome to generate two frameshift products that are implicated in viral immune evasion. How nsp1ß and PCBP associate with the viral RNA genome remains unclear. Here, we describe the purification of the nsp1ßPCBP2viral RNA complex on a scale sufficient for structural analysis using small-angle X-ray scattering and stochiometric analysis by analytical ultracentrifugation. The proteins associate with the RNA C-rich motif as a 111 complex. The monomeric form of nsp1ß within the complex differs from previously reported homodimer identified by X-ray crystallography. Functional analysis of the complex via mutational analysis combined with RNA-binding assays and cell-based frameshifting reporter assays reveal a number of key residues within nsp1ß and PCBP2 that are involved in complex formation and function. Our results suggest that nsp1ß and PCBP2 both interact directly with viral RNA during formation of the complex to coordinate this unusual PRF mechanism.
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Base de dados:
MEDLINE
Assunto principal:
Replicação Viral
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Proteínas de Ligação a RNA
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Proteínas não Estruturais Virais
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Mudança da Fase de Leitura do Gene Ribossômico
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Vírus da Síndrome Respiratória e Reprodutiva Suína
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Síndrome Respiratória e Reprodutiva Suína
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Proteínas de Ligação a DNA
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Interações Hospedeiro-Patógeno
Limite:
Animals
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Humans
Idioma:
En
Ano de publicação:
2020
Tipo de documento:
Article