Protection against fatal Sindbis virus encephalitis by beclin, a novel Bcl-2-interacting protein.
bcl-2, the prototypic cellular antiapoptotic gene, decreases Sindbis virus replication and Sindbis virus-induced apoptosis in mouse brains, resulting in protection against lethal encephalitis. To investigate potential mechanisms by which Bcl-2 protects against central nervous system Sindbis virus infection, we performed a yeast two-hybrid screen to identify Bcl-2-interacting gene products in an adult mouse brain library. We identified a novel 60-kDa coiled-coil protein, Beclin, which we confirmed interacts with Bcl-2 in mammalian cells, using fluorescence resonance energy transfer microscopy. To examine the role of Beclin in Sindbis virus pathogenesis, we constructed recombinant Sindbis virus chimeras that express full-length human Beclin (SIN/beclin), Beclin lacking the putative Bcl-2-binding domain (SIN/beclinDeltaBcl-2BD), or Beclin containing a premature stop codon near the 5' terminus (SIN/beclinstop). The survival of mice infected with SIN/beclin was significantly higher (71%) than the survival of mice infected with SIN/beclinDeltaBcl-2BD (9%) or SIN/beclinstop (7%) (P < 0.001). The brains of mice infected with SIN/beclin had fewer Sindbis virus RNA-positive cells, fewer apoptotic cells, and lower viral titers than the brains of mice infected with SIN/beclinDeltaBcl-2BD or SIN/beclinstop. These findings demonstrate that Beclin is a novel Bcl-2-interacting cellular protein that may play a role in antiviral host defense.
Pubmed ID: 9765397 RIS Download
Alphavirus Infections | Amino Acid Sequence | Animals | Antiviral Agents | Apoptosis | Apoptosis Regulatory Proteins | Beclin-1 | Chromosomes, Human, Pair 17 | Encephalitis, Viral | Female | Genes, bcl-2 | Humans | Male | Membrane Proteins | Mice | Molecular Sequence Data | Mutation | Proteins | Proto-Oncogene Proteins c-bcl-2 | RNA, Messenger | Saccharomyces cerevisiae | Sindbis Virus | Tissue Distribution | Virulence | Virus Replication