Stem II-disrupting pseudoknot does not abolish ability of Senecavirus A IRES to initiate protein expression, but inhibits recovery of virus from cDNA clone.
Vet Microbiol
; 255: 109024, 2021 Apr.
Article
en En
| MEDLINE
| ID: mdl-33713975
ABSTRACT
Senecavirus A (SVA) is classified into the genus Senecavirus in the family Picornaviridae. Its genome is a positive-sense, single-stranded and nonsegmented RNA, approximately 7300 nucleotides in length. A picornaviral genome is essentially an mRNA, which, albeit unmodified with 5' cap structure, can still initiate protein expression by the internal ribosome entry site (IRES). The SVA genome contains a hepatitis C virus-like IRES, in which a pseudoknot structure plays an important role in initiating protein expression. In this study, we constructed a set of SVA (CH-LX-01-2016 strain) minigenomes with all combinations of point mutations in its pseudoknot stem II (PKS-II). The results showed that any combination of point mutations could not significantly interfere with the IRES to initiate protein expression. Further, we constructed a full-length SVA cDNA clone, in which the PKS-II-forming cDNA motif was subjected to site-directed mutagenesis for totally disrupting the PKS-II formation in IRES. Such a modified SVA cDNA clone was transfected into BSR-T7/5 cells, consequently demonstrating that the PKS-II-disrupting IRES interfered neither with protein expression nor with antigenome replication, whereas a competent SVA could not be rescued from the cDNA clone. It was speculated that the mutated motif possibly disrupted a packaging signal for virion assembly, therefore causing the failure of SVA rescue.
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1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Picornaviridae
/
Proteínas Virales
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ARN Viral
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Regulación Viral de la Expresión Génica
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Sitios Internos de Entrada al Ribosoma
Límite:
Animals
Idioma:
En
Revista:
Vet Microbiol
Año:
2021
Tipo del documento:
Article