Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 3 de 3
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Sci Rep ; 7(1): 7120, 2017 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-28769080

RESUMO

Hepadnaviruses, including human hepatitis B virus (HBV), replicate their tiny DNA genomes by protein-primed reverse transcription of a pregenomic (pg) RNA. Replication initiation as well as pgRNA encapsidation depend on the interaction of the viral polymerase, P protein, with the ε RNA element, featuring a lower and an upper stem, a central bulge, and an apical loop. The bulge, somehow assisted by the loop, acts as template for a P protein-linked DNA oligo that primes full-length minus-strand DNA synthesis. Phylogenetic conservation and earlier mutational studies suggested the highly based-paired ε structure as crucial for productive interaction with P protein. Using the tractable duck HBV (DHBV) model we here interrogated the entire apical DHBV ε (Dε) half for sequence- and structure-dependent determinants of in vitro priming activity, replication, and, in part, in vivo infectivity. This revealed single-strandedness of the bulge, a following G residue plus the loop subsequence GUUGU as the few key determinants for priming and initiation site selection; unexpectedly, they functioned independently of a specific structure context. These data provide new mechanistic insights into avihepadnaviral replication initiation, and they imply a new concept towards a feasible in vitro priming system for human HBV.


Assuntos
Pareamento de Bases , Vírus da Hepatite B do Pato/genética , Sequências Repetidas Invertidas , Motivos de Nucleotídeos , RNA Viral/química , RNA Viral/genética , Sítio de Iniciação de Transcrição , Animais , Aptâmeros de Nucleotídeos/genética , Sequência de Bases , Sítios de Ligação , Linhagem Celular Tumoral , Galinhas , Regulação Viral da Expressão Gênica , Mutação , Conformação de Ácido Nucleico , Ligação Proteica , RNA , Replicação Viral
2.
Nat Commun ; 6: 6263, 2015 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-25672491

RESUMO

Sirtuins are a highly conserved class of NAD(+)-dependent lysine deacylases. The human isotype Sirt2 has been implicated in the pathogenesis of cancer, inflammation and neurodegeneration, which makes the modulation of Sirt2 activity a promising strategy for pharmaceutical intervention. A rational basis for the development of optimized Sirt2 inhibitors is lacking so far. Here we present high-resolution structures of human Sirt2 in complex with highly selective drug-like inhibitors that show a unique inhibitory mechanism. Potency and the unprecedented Sirt2 selectivity are based on a ligand-induced structural rearrangement of the active site unveiling a yet-unexploited binding pocket. Application of the most potent Sirtuin-rearranging ligand, termed SirReal2, leads to tubulin hyperacetylation in HeLa cells and induces destabilization of the checkpoint protein BubR1, consistent with Sirt2 inhibition in vivo. Our structural insights into this unique mechanism of selective sirtuin inhibition provide the basis for further inhibitor development and selective tools for sirtuin biology.


Assuntos
Sirtuína 2/antagonistas & inibidores , Sirtuína 2/química , Acetamidas/química , Acetamidas/farmacologia , Sequência de Aminoácidos , Domínio Catalítico , Cristalografia por Raios X , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Humanos , Cinética , Ligantes , Modelos Moleculares , Dados de Sequência Molecular , Ligação Proteica , Conformação Proteica , Tiazóis/química , Tiazóis/farmacologia
3.
Hepatology ; 50(1): 46-55, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19333911

RESUMO

UNLABELLED: Coinfection with hepatitis B virus (HBV) and hepatitis C virus (HCV) has been associated with severe liver disease and frequent progression to cirrhosis and hepatocellular carcinoma. Clinical evidence suggests reciprocal replicative suppression of the two viruses, or viral interference. However, interactions between HBV and HCV have been difficult to study due to the lack of appropriate model systems. We have established a novel model system to investigate interactions between HBV and HCV. Stable Huh-7 cell lines inducibly replicating HBV were transfected with selectable HCV replicons or infected with cell culture-derived HCV. In this system, both viruses were found to replicate in the same cell without overt interference. Specific inhibition of one virus did not affect the replication and gene expression of the other. Furthermore, cells harboring replicating HBV could be infected with cell culture-derived HCV, arguing against superinfection exclusion. Finally, cells harboring replicating HBV supported efficient production of infectious HCV. CONCLUSION: HBV and HCV can replicate in the same cell without evidence for direct interference in vitro. Therefore, the viral interference observed in coinfected patients is probably due to indirect mechanisms mediated by innate and/or adaptive host immune responses. These findings provide new insights into the pathogenesis of HBV-HCV coinfection and may contribute to its clinical management in the future.


Assuntos
Hepatite B/complicações , Hepatite B/virologia , Hepatite C/complicações , Hepatite C/virologia , Interferência Viral , Células Cultivadas/virologia , Humanos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...