TY - JOUR A1 - Hong, Liu A1 - Bräutigam, Sandra A1 - Rethwilm, Axel T1 - Expression of the human foamy virus bel-1 transactivator in insect cells N2 - The human foamy virus (HFV) bel-l transactivator protein was expressed in insect cells by a recombinant baculovirus. For the generation of the recombinant baculovirus, Acbel-1, the bel-l gene of an HFV mutant was used, that bears truncations in the bel-l overlapping bel-2 open reading frame. Acbel-1 infected Sf9 cells produced high amounts of recombinant protein of the same electrophoretic mobility (36 kD) as bel-l expressed in mammalian cells. The baculovirus expressed bel-l proteinwas readily identified by a polyclonal rabbit serum directed against bel-1 in immunoblot assay. As in mammalian cells, bel-l was predominantly localized to the nucleus of Acbel-1 infected insect cells. The baculovirus expressed bel-1 proteinwill be of use to determine the action of this novel viral transactivator more precisely. KW - Virologie KW - Human foamy virus bel-l transactivator; Expression in insect cells Y1 - 1993 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-61383 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 - Hahn, Heidi A1 - Baunach, Gerald A1 - Bräutigam, Sandra A1 - Mergia, Ayalew A1 - Neumann-Haefelin, Dieter A1 - Daniel, Muthiah D. A1 - McClure, Myra O. A1 - Rethwilm, Axel T1 - Reactivity of primate sera to foamy virus Gag and Bet proteins N2 - In order to establish criteria for the Serodiagnosis of foamy virus infections we investigated the extent to which sera from iofected individuals of human and primate origin react with structural and non-structural virus proteins in immunoblot assays. Using lysates from infected cells as the source of virus antigen, antibodies were preferentially detected against the Gag proteins and the non-structural Bet protein. Both the Gag precursor molecules of 70 and 74K apparent M\(_r\) and the cytoplasmic 60K M\(_r\) Bet protein were found to be phosphorylated, the latter being synthesized in large amounts in infected cells. Rahbit antiserum raised against recombinant human foamy virus (HFV) Gag major capsid protein cross-reacted with foamy viruses of chimpanzee, gorilla, orang-utan, rhesus monkey and Mrican green monkey origin. This was reßected by a broad cross-reactivity of the respective monkey sera to the Gag proteins of the various foamy virus isolates. Cross-reactivity of antisera against the Bet protein was restricted to viruses from man and the great apes. Recombinant Gag and Bet proteins expressed in prokaryotes or in insect cells were readily recognized by foamy virus-positive primate sera. Screening serum samples from chimpanzees with HFV Gag and Bet proteins expressed by recombinant baculoviruses revealed that 18 out of 35 (52%) were positive for Gag antibodies. Of these, 13 (72 o/o) showed antiborlies against the Bet protein, indicating that Bet antigen is of value in sero1ogical screening for foamy virus infections. KW - Virologie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-61366 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 - Aguzzi, A. A1 - Both, K. A1 - Anhauser, I. A1 - Horak, I. A1 - Rethwilm, Axel A1 - Wagner, EF. T1 - Expression of human foamy virus is differentially regulated during development in transgenic mice N2 - Tbe human foamy virus (HFV) is a recently characterized member ofthe spumavirus family. Although no diseases have been unequivocally associated with HFV infection, expression of HFV regulatory genes in transgenie mice induces a characteristic aeute neuro degenerative disease and a myopathy. To better eharaeterize the sequenee of events leading to disease, and to gain a better understanding of the underlying pathogenetic meehanisms, we have analyzed in detail the transgene expression pattern during development. Transcription of a construet containing all regulatory elements and aneillary genes of mv was analyzed by in situ hybridization and was shown to occur in two distinct phases. At midgestation, low but widespread expression was first deteeted in eells of extraembryonie tissues. Later, various tissues originating from embryonie mesoderm, neuroeetoderm, and neural erest transeribed the transgene at moderate levels. However, expression deereased dramatically during late gestation and was suppressed shortly after birth. After a latency period of up to 5 weeks, transeription of the transgene resumed in single eelJs distributed irregularly in the central nervous system and in the skeletal museIe. By the age of 8 weeks, an increasing number of eells displayed much higher expression levels than in embryonie Iife and eventually underwent severe degenerative ehanges. These findings demonstrate that HFV transgene expression is differentially regulated in development and that HFV cytotoxicity may be dose-dependent. Such biphasic pattern of expression differs from that of murine retroviruses and may be explained by the specificity of HFV regulatory elements in combination with cellular faetors. Future studies of this model system should, therefore, provide novel insights in the mechanisms controlling retrovirallatency. KW - Virologie Y1 - 1992 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-55290 ER - TY - JOUR A1 - Aguzzi, A. A1 - Wagner, E. F. A1 - Netzer, K. O. A1 - Bothe, K. A1 - Anhauser, I. A1 - Rethwilm, Axel T1 - Human foamy virus proteins accumulate in neurons and induce multinucleated giant cells in the brain of transgenic mice N2 - Humanfoamy virus (HFV) is a retrovirus encoding structural genes and, like human immunodeficiency virus and human T ceU leukemia virus I, several anciUary reading frames collectively termed the belgenes. We have previously shown that HFV transgenic mice develop an encephalopathy with neuronal loss in hippocampus and cerebral cortex. We have now raised and characterized rabbit antisera to various recombinant portions of gag, pot, env, and bel-I, the viraltransactivator. Immunoreactivity for gag and bel-I was observed in nuclei and processes of hippocampal and cortical neurons before the onset of morphological lesions and correlated with the appearance of HFV mRNA. Astrocyte-derived multinucleated giant ceUs containing HFV proteins were present in the brain oftransgenic mice coexpressingfuU- length HFV genes but not in mice expressing truncated gag and env, suggesting that these genes contain afusogenic domain. Expression of fuU-length structural genes decreased the life expectancy oftransgenic mice, implying an a4Juvant rolefor these proteins in HFV-induced brain damage. (Am] Pathol 1993, 142:1061-1072) KW - Molekularpathologie Y1 - 1993 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-47356 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 - 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 -