TY - JOUR A1 - Lindemann, Dirk A1 - Rethwilm, Axel T1 - Foamy Virus Biology and Its Application for Vector Development JF - Viruses N2 - Spuma- or foamy viruses (FV), endemic in most non-human primates, cats, cattle and horses, comprise a special type of retrovirus that has developed a replication strategy combining features of both retroviruses and hepadnaviruses. Unique features of FVs include an apparent apathogenicity in natural hosts as well as zoonotically infected humans, a reverse transcription of the packaged viral RNA genome late during viral replication resulting in an infectious DNA genome in released FV particles and a special particle release strategy depending capsid and glycoprotein coexpression and specific interaction between both components. In addition, particular features with respect to the integration profile into the host genomic DNA discriminate FV from orthoretroviruses. It appears that some inherent properties of FV vectors set them favorably apart from orthoretroviral vectors and ask for additional basic research on the viruses as well as on the application in Gene Therapy. This review will summarize the current knowledge of FV biology and the development as a gene transfer system. KW - terminal gag domain KW - env leader protein KW - enhance viral transcription KW - subviral particle release KW - cell-cycle dependence KW - foamyviruses KW - retroviral vectors KW - LAD KW - Fanconi Anemia KW - cis-acting sequences KW - dna-binding protein KW - pol messenger-rna KW - reverse-transcriptase KW - gene-expression Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-139811 VL - 3 IS - 5 ER - TY - CHAP A1 - Maurer, B. A1 - Bannert, H. A1 - Rethwilm, Axel A1 - Darai, B. A1 - Flügel, R. M. T1 - Characterization of the env gene and of two novel coding regions of the human spumaretrovirus N2 - Recombinant clones harboring retroviral DNA were established. The nucleotide sequence of the central and 3' region of the genome of the human spumaretrovirus was determined. The 5' end of the deduced protein sequence was homologaus to the endonuclease domain of retroviral reverse transcriptases. A small intergenic region is followed by a lang open reading frame of 985 aminoacid residues that according to its genomic location and structural features is a typical retroviral env gene. Surprisingly, the postenv region contains two open reading frames that encodes two novel retroviral genes, termed bel-l and bel-2. The 3' LTR is 963 nucleotides lang and contains the signal sequences characteristic for transcriptional regulation of retrovirus genomes. KW - Spumaviren Y1 - 1988 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-86334 ER - TY - JOUR A1 - Maurer, Bernd A1 - Serfling, Edgar A1 - ter Meulen, Volker A1 - Rethwilm, Axel T1 - Transcription factor AP-1 modulates the activity of the human foamy virus long terminal repeat N2 - The human foamy virus (HFV) contains within the UJ region of its long terminal repeat (L TR) three perfect consensus sequences for the binding of the inducible transcription factor AP-1. Results of DNase I footprint protection and gel retardation assays demonstrated that proteins in extracts of HeLa and BHK-21 cells as weil as bacterially expressed Jun and Fos proteins bind to these AP-1 sites. By conducting transient expression assays using chloramphenicol acetyltransferase plasmids carrying LTR sequences with point-mutated AP-1 sites it was found that the three AP-1 sites contribute to the optimal activity ofthe HFV promoter. It is shown that lnduction of the HFV L TR by 12-O-tetradecanoylphorbol-13-acetate (TPA) and serum factors is mediated through the AP-1 sites. KW - Virologie Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-61444 ER - TY - CHAP A1 - Mori, Kazuyasu A1 - Rethwilm, Axel A1 - Schwinn, Andreas A1 - Horak, Ivan T1 - Replication of human immunodeficiency virus type 1 in human t-cells expressing antisense RNA N2 - No abstract available. KW - HIV Y1 - 1990 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-86426 ER - TY - JOUR A1 - Müller, J. G. A1 - Krenn, V. A1 - Schindler, C. A1 - Czub, S. A1 - Stahl-Henning, C. A1 - Coulibaly, C. A1 - Hunsmann, G. A1 - Kneitz, C. A1 - Kerkau, Thomas A1 - Rethwilm, Axel A1 - terMeulen, Volker T1 - Alterations of thymus cortical epithelium and interdigitating dendritic cells but no increase of thymocyte cell death in the early course of simian immunodeficiency virus infection N2 - No abstract available Y1 - 1993 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-32583 ER - TY - JOUR A1 - Müller, J. A1 - Krenn, V. A1 - Czub, S. A1 - Schindler, C. A1 - Kneitz, C. A1 - Kerkau, T. A1 - Stahl-Henning, C. A1 - Coulibaly, C. A1 - Hunsmann, G. A1 - Rethwilm, Axel A1 - ter Meulen, Volker A1 - Müller-Hermelink, H. K. T1 - The thymus in SIV infection N2 - no abstract available KW - HIV-Infektion KW - Tierversuch KW - Tiermodell KW - Retroviren-Infektion KW - Kongress KW - Hamburg Y1 - 1993 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-80265 ER - TY - JOUR A1 - Netzer, Kai O. A1 - Rethwilm, Axel A1 - Maurer, Bernd A1 - ter Meulen, Volker T1 - Identification of the major immunogenic structural proteins of human foamy virus N2 - We have identified the major immunogenic structural proteins of the human foamy virus (HFV), a distinct member of the foamy virus subfamily of Retroviridae. Radiolabelied viral proteins were immunoprecipitated from HFV -infected cells by foamy virus antisera of human and non-human primate origin. Precipitated viral proteins were in the range of 31 K to 170K. Labelling of proteins with [\(^{14}\)C]glucosamine or with [\(^{35}\)S]methionine in the presence oftunicamycin, as well as endo-ß-N-acetylglycosaminidase Hand F treatment of [\(^{35}\)S]methionine-labelled proteins, revealed three viral glycoproteins of approximately 170K, 130K and 47K, most likely representing the env gene-encoded precursor, the surface glycoprotein and the transmembrane protein of HFV, respectively. KW - Virologie Y1 - 1990 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-61477 ER - TY - JOUR A1 - Netzer, Kai O. A1 - Schliephake, Andreas A1 - Maurer, Bernd A1 - Watanabe, Rihito A1 - Aguzzi, Adriano A1 - Rethwilm, Axel T1 - Identification of pol-related gene products of human foamy virus N2 - Human foamy viruspol gene fragments were molecularly cloned into a procaryotic expression vector. The expression pattern of the cloned fragments and nucleotide sequence analysis of the 5' pol gene region revealed that in HFV the protease (PR) is located in the pol open reading frame. Purified recombinant proteins were used to generate antibodies in rats. ln immunoblot assay, using infected cells as antigen, a precursor protein with an apparent molecular mass (M,) of 127K was identified by antibodies directed against the reverse transcriptase (RT), RNaseH, or integrase (IN) domeins of pol. With concentrated virus as antigen, the RT and RNaseH antibodies recognized a protein of 80K, the IN antiserum recognized a protein of 40K, and the PR antiserum detected a protein of approximately 10K. KW - Virologie Y1 - 1993 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-61429 ER - TY - JOUR A1 - Neumann-Haefelin, D. A1 - Rethwilm, Axel A1 - Bauer, G. A1 - Gudat, F. A1 - zur Hausen, H. T1 - Characterization of a foamy virus isolated from Cercopithecus aethiops lymphoblastoid cells N2 - A virus derived from cells of a Iymphoblastoid line originating from the lymph node of a healthy African green monkey was characterized as a typical member of the foamy virus subgroup of rctroviridac by its morphological, physicochemical, biological and biochemical properties (reverse transcriptase actvity). Besides the usual host range of foamy viruses, the isolated strain revealed a remarkable T -lymphotropism, distinguishing it from the prototypes of foamy viruses previously isolated from African green monkeys. Two foamy virus infectious are demonstrated in human contacts of the African green monkey colony, with the animal barbauring the isolate. KW - Virologie Y1 - 1983 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-61538 ER - TY - CHAP A1 - Rethwilm, Axel A1 - Baunach, Gerald A1 - Mori, Kazuyasu A1 - ter Meulen, Volker T1 - Transactivation of HIV by human spumaretrovirus N2 - To study the activation of HIV by human spumaretrovirus (HSRV) the long terminal repeats (LTRs) of HSRV, HIVl and HIV2 were examined with respect to their ability to function as transcriptional promoters in virus infected and uninfected cells. Transient transfections using plasmids in which the L TRs of the three viruses were coupled to the bacterial chloramphenicol acetyltransferase (CA T) gene revealed (i) the level of cat gene expression directed by the HSRV LTR was markedly increased in HSRV infected cells compared to uninfected cells, (ii) cat gene expression driven by the HIV1 LTR, but not by the HIV2 LTR could be enhanced upon HSRV infection, whereas (iii) neither in HIV1 nor in HIV2 infected cells an effect on HSRV LTR driven cat geneexpression was detected. KW - HIV Y1 - 1990 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-86436 ER - TY - JOUR A1 - Rethwilm, Axel A1 - Baunach, Gerald A1 - Netzer, Kai O. A1 - Maurer, Bernd A1 - Borisch, Bettina A1 - ter Meulen, V.olker T1 - Infectious DNA of the human spumaretrovirus N2 - An infectious molecular clone (pHSRV) of the human Spumaretrovirus (HSRV) was constructed using viral DNA and cDNA clones. The infectivity of pHSRV was proven by transfection of cell cultures and subsequent infection of susceptible cultures with cell free transfection derlved virus. pHSRV derived virus produced foamy virus typical cytopathic effects in susceptible cultures. lnfected cells could be stained specifically with foamy virus antisera by means of indirect immunofluorescence. Radiolmmunoprecipltatlon revealed the presence of characteristic HSRV structural proteins in pHSRV infected cultures. By cotransfection of pHSRV and an indicator plasmid it was found that pHSRV is able to transactivate the viral L TR. Viral transcripts were found to be approximately 200 bases Ionger in pHSRV infected cultures compared to wildtype infected cultures. This difference is most likely due to an Insertion of DNA of non-viral origin ln the U3 region of the 3'L TR of the infectious clone. KW - Virologie Y1 - 1990 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-61495 ER - TY - JOUR A1 - Rethwilm, Axel A1 - Darai, G. A1 - Rösen, A. A1 - Maurer, Bernd A1 - Flügel, Rolf M. T1 - Molecular cloning of the genome of human spumaretrovirus N2 - DNA ofhuman spumaretrovirus (HSRV) was cloned from both cDNA and from viral DNA into phage A and bacterial plasmid vectors. The recombinant plasm.ids harboring viral DNA were characterized by Southern blot hybridization and restriction mapping. Physical maps were constructed from cDNA and found to be colinear with the restriction maps obtained from viral DNA. The recombinant clones isolated contained viral DNA inserts which rangein size from 2.2 kb to 15.4 kb. The recombinant clones allowed to construct a physical map of the complete HSRV provirus of 12.2 kb. KW - Virologie Y1 - 1987 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-61518 ER - TY - JOUR A1 - Rethwilm, Axel A1 - Erlwein, Otto A1 - Baunach, Gerald A1 - Mauerer, Bernd A1 - ter Meulen, Volker T1 - The transcriptional transactivator of human foamy virus maps to the bel 1 genomic region N2 - The human foamy virus (HFV) genome possesses three open reading frames (bel I, 2, and 3) located between env and the 3' long terminal repeat. By analogy to other human retroviruses this region was selected as the most Iikely candidate to encode the viral transactivator. ResuIts presented here confirmed this and showed further that a deletion introduced only into the bell open reading frame of a plasmid derived from an infectious molecular clone of HFV abolished transactivation. In contrast, deletions in bel 2 and bel 3 had only minor effects on the ability to transactivate. The role of the bel I genomic region as a transactivator was further investigated by eukaryotic expression of a genome fragment of HFV spanning the bel I open reading frame. A construct expressing bell under control of a heterologous promoter was found to transactivate the HFV long terminal repeat in a dose-dependent fashion. Furthermore, it is shown that the U3 region of the HFV long terminal repeat is sufficient to respond to the HFV transactivator. KW - Virologie Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-47342 ER - TY - JOUR A1 - Rethwilm, Axel A1 - Mori, Kazuyasu A1 - Maurer, Bernd A1 - ter Meulen, Volker T1 - Transacting transcriptional activation of human spumaretrovirus LTR in infected cells N2 - The long terminal repeat (LTR) of the human spumaretrovirus (HSRV) was examined with respect to its ability to function as transcriptional promotor in virus-infected and uninfected cells. Transient transfections using a plasmid in which the 3' L TR of HSRV was coupled to the bacterial chloramphenicol cetyltransferase (cat) gene revealed that the Ievei of HSRV LTR-directed cat gene expression was markedly increased in HSRV-infected cells compared to uninfected cells. Northern blot analysis of cat mRNA from transfected cultures suggests that transactivation of HSRVdirected gene expression occurs at the transcriptionallevel. KW - Virologie Y1 - 1990 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-61488 ER - TY - JOUR A1 - Schliephake, Andreas W. A1 - Rethwilm, Axel T1 - Nuclear Localization of Foamy Virus Gag Precursor Protein N2 - All foamy viruses give rise to a strong nuclear staining when infected cells are reacted with sera from infected hosts. This nuclear ftuorescence distinguishes foamy viruses from all other retroviruses. The experiments reported here indicate that the foamy virus Gag precursor protein is transiently located in the nuclei of infected cells and this is the likely reason for the typical foamy virus nuclear fluorescence. By using the vaccinia virus expression system, a conserved basic sequence motif in the nucleocapsid domain of foamy virus Cag proteins was identified to be responsible for the nuclear transport of the gag precursor molecule. Tbis motif was also found to be able to direct a heterologous protein, the Gag protein of human immunodeficiency virus, into the nucleus. KW - Virologie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-61371 ER - TY - JOUR A1 - Shityakov, Sergey A1 - Förster, Carola A1 - Rethwilm, Axel A1 - Dandekar, Thomas T1 - Evaluation and Prediction of the HIV-1 Central Polypurine Tract Influence on Foamy Viral Vectors to Transduce Dividing and Growth-Arrested Cells N2 - Retroviral vectors are potent tools for gene delivery and various biomedical applications. To accomplish a gene transfer task successfully, retroviral vectors must effectively transduce diverse cell cultures at different phases of a cell cycle. However, very promising retroviral vectors based on the foamy viral (FV) backbone lack the capacity to efficiently transduce quiescent cells. It is hypothesized that this phenomenon might be explained as the inability of foamy viruses to form a pre-integration complex (PIC) with nuclear import activity in growth-arrested cells, which is the characteristic for lentiviruses (HIV-1). In this process, the HIV-1 central polypurine tract (cPPT) serves as a primer for plus-strand synthesis to produce a “flap” element and is believed to be crucial for the subsequent double-stranded cDNA formation of all retroviral RNA genomes. In this study, the effects of the lentiviral cPPT element on the FV transduction potential in dividing and growth-arrested (G1/S phase) adenocarcinomic human alveolar basal epithelial (A549) cells are investigated by experimental and theoretical methods. The results indicated that the HIV-1 cPPT element in a foamy viral vector background will lead to a significant reduction of the FV transduction and viral titre in growth-arrested cells due to the absence of PICs with nuclear import activity. KW - Evaluation KW - Prognose KW - HIV KW - Spumaviren KW - Einfluss Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-112763 ER - TY - JOUR A1 - Siwka, Wieslaw A1 - Schwinn, Andreas A1 - Baczko, Knut A1 - Pardowitz, Iancu A1 - Mhalu, Fred A1 - Shao, John A1 - Rethwilm, Axel A1 - ter Meulen, Volker T1 - vpu and env sequence variability of HIV-1 isolates from Tanzania N2 - No abstract available KW - Virologie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-61355 ER - TY - JOUR A1 - Spannaus, Ralf A1 - Hartl, Maximilian J. A1 - Wöhrl, Birgitta M. A1 - Rethwilm, Axel A1 - Bodem, Jochen T1 - The prototype foamy virus protease is active independently of the integrase domain N2 - Background: Recently, contradictory results on foamy virus protease activity were published. While our own results indicated that protease activity is regulated by the viral RNA, others suggested that the integrase is involved in the regulation of the protease. Results: To solve this discrepancy we performed additional experiments showing that the protease-reverse transcriptase (PR-RT) exhibits protease activity in vitro and in vivo, which is independent of the integrase domain. In contrast, Pol incorporation, and therefore PR activity in the viral context, is dependent on the integrase domain. To further analyse the regulation of the protease, we incorporated Pol in viruses by expressing a GagPol fusion protein, which supported near wild-type like infectivity. A GagPR-RT fusion, lacking the integrase domain, also resulted in wild-type like Gag processing, indicating that the integrase is dispensable for viral Gag maturation. Furthermore, we demonstrate with a trans-complementation assays that the PR in the context of the PR-RT protein supports in trans both, viral maturation and infectivity. Conclusion: We provide evidence that the FV integrase is required for Pol encapsidation and that the FV PR activity is integrase independent. We show that an active PR can be encapsidated in trans as a GagPR-RT fusion protein. KW - Medizin KW - Foamy virus KW - Regulation of protease activity KW - PARM KW - Integrase KW - GagPol fusion protein Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-75370 ER -