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  • 1
    Keywords: CELLS ; EXPRESSION ; Germany ; CLONING ; GENE ; PROTEIN ; PROTEINS ; transcription ; RELEASE ; DNA ; FAMILY ; DOMAIN ; CARCINOGENESIS ; CONTRAST ; PARTICLES ; virus ; DEGRADATION ; REPLICATION ; ANTIVIRAL ACTIVITY ; CONSTRUCTION ; IMMUNODEFICIENCY-VIRUS ; RE ; spumaretrovirus ; zoonosis ; cytidine deamination ; HIV-1 VIF ; HYPERMUTATION ; restriction factor ; virion infectivity factor
    Abstract: Genome hypermutation of different orthoretroviruses by cellular cytidine deaminases of the APOBEC3 family during reverse transcription has recently been observed. Lentiviruses like HIV-1 have acquired proteins preventing genome editing in the newly infected cell. Here we show that feline foamy virus (FFV), a typical member of the foamy retrovirus subfamily Spumaretrovirinae, is also refractory to genome deamination. APOBEC3-like FFV genome editing in APOBEC3-positive feline CRFK cells only occurs when the accessory FFV Bet protein is functionally inactivated. Editing of bet-deficient FFV genomes is paralleled by a strong decrease in FFV titer. In contrast to lentiviruses, cytidine deamination already takes place in APOBEC3-positive FFV-producing cells, because edited proviral DNA genomes are consistently present in released particles. By cloning the feline APOBEC3 orthologue, we found that its homology to the second domain of human APOBEC3F is 48%. Expression of feline APOBEC3 in APOBEC3-negative human 293T cells reproduced the effects seen in homologous CRFK cells: Bet-deficient FFV displayed severely reduced titers, high-level genome editing, reduced particle release, and suppressed Gag processing. Although WT Bet efficiently preserved FFV infectivity and genome integrity, it sustained particle release and Gag processing only when fe3 was moderately expressed. Similar to lentiviral Vif proteins, FFV Bet specifically bound feline APOBEC3. In particles from Bet-deficient FFV, feline APOBEC3 was clearly present, whereas its foamy viral antagonist Bet was undetectable in purified WT particles. This is the first report that, in addition to lentiviruses, the foamy viruses also developed APOBEC3-counteracting proteins
    Type of Publication: Journal article published
    PubMed ID: 15911774
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  • 2
    Keywords: CELLS ; CELL ; Germany ; human ; SYSTEM ; SYSTEMS ; DISEASE ; GENOME ; PROTEIN ; RESPONSES ; CARCINOGENESIS ; animals ; BIOLOGY ; antibodies ; antibody ; virus ; IDENTIFICATION ; HUMANS ; RETROVIRUSES ; ASSAY ; NUMBER ; REPLICATION ; ANTIBODY-RESPONSES ; PREVALENCE ; foamy virus ; glutathione-S-transferase ; SERUM ; ELISA ; PROGRAM ; RE ; zoonosis ; ASSAYS ; BOVINE ; USA ; spumavirus ; animal ; diagnostic marker ; humoral immunity ; virology ; enzyme-linked immunosorbent assay ; milk ; DAIRY-CATTLE ; INFECTED CATS ; milk-borne infection ; SYNCYTIAL VIRUS
    Abstract: The biology of foamy viruses, their mode of transmission and disease potential in their natural host and after interspecies transmission are largely unknown. To gain insights into the prevalence of bovine foamy virus (BEV) and its zoonotic potential, enzyme-linked immunosorbent assays (ELISAs) were established to determine antibody responses against Gag, Env, and the non-structural protein Bet in bovine serum and milk. In Polish cattle, strong Gag reactivity was most frequent (41.5%) and strongly associated with Bet antibodies, Env antibodies were less frequent. German cattle showed a low overall BFV antibody prevalence of 6.8%. Besides clearly BFV-positive animals, a substantial number of weakly reacting cattle were identified. BFV-specific antibodies were also detectable in milk. BFV was isolated from PBLs and milk cells of BFV-positive cattle but not from antibody-negative or weakly reacting animals. The implications of these findings for the potential interspecies transmission of BEV to humans will be discussed. (C) 2007 Elsevier Inc. All rights reserved
    Type of Publication: Journal article published
    PubMed ID: 17408715
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  • 3
    Keywords: Germany ; human ; POPULATION ; GENE ; PROTEIN ; MOLECULAR CHARACTERIZATION ; INFECTION ; animals ; CATS ; GRAVES-DISEASE ; RETROVIRUSES ; VECTORS ; REPLICATION ; INFECTIONS ; foamy virus ; GAG ; pathogen ; PATHOGENS ; spumaretrovirus ; zoonosis
    Abstract: Human infections by pathogens originating from animals is a permanent threat. In particular the potency of transmition within the human population is the prerequisite for an epidemic or pandemic distribution of the new pathogen. This scenario has happened in the past on several independent occasions with the simian immunodeficiency viruses, which led to the HIV (AIDS) pandemic. The same appeared to have happened with the SARS coronavirus epidemic, although the authentic animal host has not yet been defined. This review summarizes well documented cases of transmission of various simian foamyviruses to man and discusses the zoonotic potential of nonhuman foamyvirus from cats, cattle and horses
    Type of Publication: Journal article published
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  • 4
    Keywords: EXPRESSION ; Germany ; human ; DISEASE ; DISTINCT ; GENE ; PROTEIN ; PROTEINS ; RESPONSES ; INFECTION ; antibodies ; virus ; IDENTIFICATION ; ASSAY ; REPLICATION ; PREVALENCE ; foamy virus ; RETROVIRAL VECTORS ; glutathione-S-transferase ; SERUM ; ELISA ; VIRUS-INFECTION ; ASSAYS ; IMMUNODEFICIENCY VIRUS ; diagnostic marker ; APOBEC3 ; CAPTURE ELISA ; humoral immunity ; LEADER PROTEIN
    Abstract: Spumaretroviruses or foamy viruses constitute a distinct subfamily of retroviruses. The biology of foamy viruses within the authentic host, their mode of transmission, and disease potential in the authentic host or after zoonotic transmission into human or other species are almost unknown. Using feline foamy virus (FFV) as model system, we established modular enzyme-linked immunosorbent assays (ELISA) Suited to determine feline IgG and IgM antibody responses against structural and non-structural FFV proteins. We validated the ELISAs with standard reference sera. In 99 cats admitted to a Swiss veterinary hospital, overall FFV Gag antibody prevalence was 36%, reactivity against Env and the non-structural protein Bet each was about 25%, and 19% of the sera were directed against all three FFV antigens. With one exception, all Bet- and/ or Env-positive sera were also positive for Gag. In this small epidemiological pilot study, FFV antibodies were not significantly associated with clinical disease. (c) 2005 Elsevier Inc. All rights reserved
    Type of Publication: Journal article published
    PubMed ID: 16297422
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  • 5
    Keywords: CELLS ; EXPRESSION ; CELL ; Germany ; human ; THERAPY ; EXPOSURE ; LONG-TERM ; GENE ; GENE-EXPRESSION ; gene therapy ; TRANSDUCTION ; gene transfer ; GENE-TRANSFER ; MARKER ; BIOLOGY ; TARGET ; virus ; DELETION ; VECTOR ; PROMOTER ; NUMBER ; PROMOTERS ; genetics ; EFFICIENT ; REPLICATION ; GENE-THERAPY ; RETROVIRAL VECTORS ; CONSTRUCTION ; heredity ; FELINE FOAMY VIRUS ; ARRAY ; TERMINAL GAG DOMAIN ; PROFILES ; ENV LEADER PROTEIN ; UBIQUITIN ; RETROVIRUS ; ACCESSORY BET PROTEIN ; biosafety ; deficient vector ; lacZ ; NOD/SCID-REPOPULATING CELLS ; SIN vector ; UBIQUITIN-C
    Abstract: As serious side effects affected recent virus-mediated gene transfer studies, novel vectors with improved safety profiles are urgently needed. In the present study, replication-deficient retroviral vectors based on feline foamy virus (FFV) were constructed and analyzed. The novel FFV vectors are devoid of almost the complete env gene plus the internal promoter - accessory bel gene cassette including the gene for the viral transcriptional transactivator Bel1/Tas. In these Bel1/Tas-independent vectors, expression of the lacZ (beta-galactosidase) marker gene is directed by the heterologous, constitutively active human ubiquitin C promoter (ubl). Env-transcomplemented vectors have unconcentrated titers of more than 10(5) transducing units/ml. The vectors allow efficient transduction of a broad array of diverse target cells, which can be increased by repeated vector exposure. However, the number of lacZ marker gene expressing cells decreased slightly upon serial passages of the transduced cells. Vectors carrying a self-inactivating (SIN) deletion of the TATA box and most parts of the viral promoter were not rescued by wt FFV whereas those with the intact or a partially deleted promoter were readily reactivated. This finding indicates that the viral promoters are in fact non-functional, pointing to a highly advantageous safety profile of these new FFV-ubi-lacZ-SIN vectors
    Type of Publication: Journal article published
    PubMed ID: 17203107
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