RESUMEN
Coronavirus disease 19 is caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) enveloped virus with a single-stranded positive-sense ribonucleic acid (RNA) genome. The CoV non-structural protein (nsp) 1 is a multifunctional protein that undergoes translation shutoff, messenger RNA (mRNA) cleavage, and RNA binding. The C-terminal region is involved in translational shutoff and RNA cleavage. The N-terminal region of SARS-CoV-2 nsp1 is highly conserved among isolated SARS-CoV-2 variants. However, the I-004 variant, isolated during the early SARS-CoV-2 pandemic, lost eight amino acids in the nsp1 region. In this study, we showed that the eight amino acids are important for viral replication in infected interferon-incompetent cells and that the recombinant virus that lost these amino acids had low pathogenicity in the lungs of hamster models. The loss of eight amino acids-induced mutations occurred in the 5' untranslated region (UTR), suggesting that nsp1 contributes to the stability of the viral genome during replication.
Asunto(s)
Genoma Viral , SARS-CoV-2 , Proteínas no Estructurales Virales , Replicación Viral , Animales , Proteínas no Estructurales Virales/genética , Proteínas no Estructurales Virales/metabolismo , Proteínas no Estructurales Virales/química , SARS-CoV-2/genética , SARS-CoV-2/fisiología , SARS-CoV-2/metabolismo , Humanos , Cricetinae , COVID-19/virología , Chlorocebus aethiops , ARN Viral/genética , ARN Viral/metabolismo , Células Vero , Secuencia de Aminoácidos , Mutación , Mesocricetus , Regiones no Traducidas 5'RESUMEN
Avian rotaviruses A (RVAs) are occasionally transmitted to animals other than the original hosts across species barriers. Information on RVAs carried by various bird species is important for identifying the origin of such interspecies transmission. In this study, to facilitate an understanding of the ecology of RVAs from wild birds, we characterized all of the genes of an RVA strain, JC-105, that was detected in a fecal sample of a large-billed crow (Corvus macrorhynchos) in Japan. All of the genes of this strain except for the VP4 and VP7 genes, which were classified as novel genotypes (P[56] and G40, respectively), were closely related to those of the avian-like RVA strain detected from a raccoon, indicating the possibility that crows had been involved in the transmission of avian RVAs to raccoons. Our findings highlight the need for further viral investigations in wild birds and mammals to understand the mechanisms of avian-to-mammal RVA transmission.