Foamy virus can establish lifelong persistent infection in mammal hosts without inducing diseases. Such special characteristic stimulates the interests of researchers. As reported, the accessory protein Bet of foamy virus could regulate the gene expression and infection cycle of foamy virus and take part in the generation of chronic viral infection. And also, Bet might prevent the host cellular defense factor APO-BEC3 from interfering the replication of virus and play a role in maintaining viral persistent infection. In order to elucidate the roles of Bet in the foamy virus replication and infection, this review summarized the research progress of Bet protein reported in recent years.
Animals ; Gene Expression Regulation, Viral ; Humans ; Retroviridae Infections ; immunology ; virology ; Retroviridae Proteins ; genetics ; metabolism ; Spumavirus ; genetics ; metabolism

Animals ; HIV Long Terminal Repeat ; genetics ; Humans ; Promoter Regions, Genetic ; genetics ; Spumavirus ; genetics ; Viral Proteins ; genetics ; metabolism

Bel1, a transactivator of prototype foamy virus (PFV), plays pivotal roles in the replication of PFV. Previous studies have shown that Bel1 bears a nuclear localization signal (NLS), but its amino acid sequence remains unclear and the corresponding importins have not been identified. In this report, we inserted various fragments of Bel1 into an EGFP-GST fusion protein and investigated their subcellular localization by fluorescence microscopy. We found that the 215PRQKRPR221 fragment could direct nuclear localization, which accords with the consensus sequence K(K/R)X(K/R) of monopartite NLS. Point mutation experiments revealed that K218, R219, and R221 are essential for the nuclear localization of Bel1. The results of the GST-pulldown showed that the Bel1 fragment with residues 215-223, which bears the NLS, interacts with KPNA1, KPNA6, and KPNA7. This result suggests that KPNA1, KPNA6, and KPNA7 maybe involved in Bel1 nuclear translocation.
Cell Line ; Cell Nucleus ; genetics ; metabolism ; virology ; Humans ; Nuclear Localization Signals ; genetics ; metabolism ; Protein Binding ; Protein Transport ; Retroviridae Infections ; genetics ; metabolism ; virology ; Retroviridae Proteins ; chemistry ; genetics ; metabolism ; Spumavirus ; chemistry ; genetics ; physiology ; Trans-Activators ; chemistry ; genetics ; metabolism ; alpha Karyopherins ; genetics ; metabolism

Mesenchymal stem cells (MSCs) have received considerable attention for various therapeutic approaches in recent years. MSCs are also easy to genetically modify to express therapeutic genes by using lentiviral vectors. Because of the similarities in genetics, physiology and metabolism between non-human primates (NHPs) and humans, NHPs models are invaluable for researching human disorders and for developing therapeutic strategies. Therefore, MSCs derived from NHPs could be a powerful tool for cell therapy and genetic engineering. Studies from captive and free-ranging adult NHPs show that up to 100% were infected with simian foamy virus (SFV). In this study, we found that all cultured MSCs derived from adult cynomolgus monkey were infected with SFV by RT-PCR. Therefore, antiviral drugs must be added in MSCs culture. However, because of SFV infection and additive antiviral drugs, the infection efficiency of the lentiviral vectors reduced significantly. In this study, we improved the infection efficiency by disabled antiviral drugs before lentiviral infection. It might be provide technical assistance for the culture of adult cynomolgus monkey MSCs as genetically engineered cells applied to clinical and experimental research.
Animals ; Bone Marrow Cells ; cytology ; Cell Differentiation ; Genetic Vectors ; genetics ; Green Fluorescent Proteins ; genetics ; Lentivirus ; genetics ; Macaca fascicularis ; Mesenchymal Stromal Cells ; cytology ; virology ; Simian foamy virus ; physiology ; Transduction, Genetic