- Vaccinia virus replication is not affected by APOBEC3 family members (2006)
- The potential use of variola virus, the causative agent of smallpox, as a bioweapon and the endemic presence of monkeypox virus in Africa demonstrate the need for better therapies for orthopoxvirus infections. Chemotherapeutic approaches to control viral infections have been less successful than those targeting bacterial infections. While bacteria commonly reproduce themselves outside of cells and have metabolic functions against which antibiotics can be directed, viruses replicate in the host cells using the cells' metabolic pathways. This makes it very difficult to selectively target the virus without damaging the host. Therefore, the development of antiviral drugs against poxviruses has initially focused on unique properties of the viral replication cycle or of viral proteins that can be selectively targeted. However, recent advances in molecular biology have provided insights into host factors that represent novel drug targets. The latest anti-poxvirus drugs are kinase inhibitors, which were originally developed to treat cancer progression but in addition block egress of poxviruses from infected cells. This review will summarize the current understanding of anti-poxvirus drugs and will give an overview of the development of the latest second generation poxvirus drugs.
- Functions, structure, and read-through alternative splicing of feline APOBEC3 genes (2008)
- Background Over the past years a variety of host restriction genes have been identified in human and mammals that modulate retrovirus infectivity, replication, assembly, and/or cross-species transmission. Among these host-encoded restriction factors, the APOBEC3 (A3; apolipoprotein B mRNA-editing catalytic polypeptide 3) proteins are potent inhibitors of retroviruses and retrotransposons. While primates encode seven of these genes (A3A to A3H), rodents carry only a single A3 gene. Results Here we identified and characterized several A3 genes in the genome of domestic cat (Felis catus) by analyzing the genomic A3 locus. The cat genome presents one A3H gene and three very similar A3C genes (a-c), probably generated after two consecutive gene duplications. In addition to these four one-domain A3 proteins, a fifth A3, designated A3CH, is expressed by read-through alternative splicing. Specific feline A3 proteins selectively inactivated only defined genera of feline retroviruses: Bet-deficient feline foamy virus was mainly inactivated by feA3Ca, feA3Cb, and feA3Cc, while feA3H and feA3CH were only weakly active. The infectivity of Vif-deficient feline immunodeficiency virus and feline leukemia virus was reduced only by feA3H and feA3CH, but not by any of the feA3Cs. Within Felidae, A3C sequences show significant adaptive selection, but unexpectedly, the A3H sequences present more sites that are under purifying selection. Conclusion Our data support a complex evolutionary history of expansion, divergence, selection and individual extinction of antiviral A3 genes that parallels the early evolution of Placentalia, becoming more intricate in taxa in which the arms race between host and retroviruses is harsher.