RESUMO
Influenza A virus mutants expressing C-terminally deleted forms of the NS1 protein (NS1-81 and NS1-110) were generated by plasmid rescue. These viruses were temperature sensitive and showed a small plaque size at the permissive temperature. The accumulation of virion RNA in mutant virus-infected cells was reduced at the restrictive temperature, while the accumulation of cRNA or mRNA was not affected, indicating that the NS1 protein is involved in the control of transcription versus replication processes in the infection. The synthesis and accumulation of late virus proteins were reduced in NS1-81 mutant-infected cells at the permissive temperature and were essentially abolished for both viruses at the restrictive temperature, while synthesis and accumulation of nucleoprotein (NP) were unaffected. Probably as a consequence, the nucleocytoplasmic export of virus NP was strongly inhibited at the restrictive temperature. These results indicate that the NS1 protein is essential for nuclear and cytoplasmic steps during the virus cycle.
Assuntos
Genes Virais , Vírus da Influenza A/genética , Vírus da Influenza A/metabolismo , RNA Viral/biossíntese , Proteínas não Estruturais Virais/genética , Transporte Ativo do Núcleo Celular , Animais , Células COS , Linhagem Celular , Cães , Expressão Gênica , Humanos , Vírus da Influenza A/crescimento & desenvolvimento , Mutação , RNA Viral/genética , Deleção de Sequência , Temperatura , Transcrição Gênica , Proteínas da Matriz Viral/biossíntese , Proteínas da Matriz Viral/genéticaRESUMO
All viruses with negative-sense RNA genomes encode a single-strand RNA-binding nucleoprotein (NP). The primary function of NP is to encapsidate the virus genome for the purposes of RNA transcription, replication and packaging. The purpose of this review is to illustrate using the influenza virus NP as a well-studied example that the molecule is much more than a structural RNA-binding protein, but also functions as a key adapter molecule between virus and host cell processes. It does so through the ability to interact with a wide variety of viral and cellular macromolecules, including RNA, itself, two subunits of the viral RNA-dependent RNA polymerase and the viral matrix protein. NP also interacts with cellular polypeptides, including actin, components of the nuclear import and export apparatus and a nuclear RNA helicase. The evidence for the existence of each of these activities and their possible roles in transcription, replication and intracellular trafficking of the virus genome is considered.
Assuntos
Nucleoproteínas , Orthomyxoviridae/fisiologia , Proteínas de Ligação a RNA/fisiologia , Proteínas do Core Viral/fisiologia , Replicação Viral , Actinas/fisiologia , Transporte Biológico , Carioferinas/fisiologia , Proteínas do Nucleocapsídeo , RNA/metabolismo , RNA Viral/biossíntese , Ribonucleoproteínas/metabolismo , Proteínas do Core Viral/químicaRESUMO
La cronobiología estudia variaciones predecibles que se producen en todas las formas de vida, es decir, los ritmos y las tendencia. Cada variable o sistema fisiológico presenta una estructura en el tiempo, la cual está cifrada genéticamente, y puede expresarse en ausencia de variaciones cíclicas ambientales; sin embargo, normalmente, los ritmos biológicos están ajustados a ciclos geofísicos. La cronobiología también cuantifica las características de los ritmos biológicos, aportando medidas de la amplitud y del tiempo (fase y período), y una media normalmente más precisa y más correcta que la media aritmética. La correcta medida de los ritmos biológicos ha permitido avances de consideración en el conocimiento de sus mecanismos fisiológicos de origen y expresión. El empleo de la información sobre estos ritmos en medicina está abriendo nuevas perspectivas en la prevención, diagnóstico y tratamiento de las enfermedades. Asimismo, la cronobiología aplicaciones en el mejoramiento de la calidad de vida pues facilita al individuo el realizar un autocontrol de su estado de salud.
