title: Generation of an improved foamy virus vector by dissection of cis-acting sequences.
abstract: In contrast to other retroviruses, foamy viruses (FVs) generate their Pol protein precursor independently of the Gag protein from a spliced mRNA. The exact mechanism of Pol protein incorporation into the viral capsid is poorly understood. Previously, we showed that Pol encapsidation critically depends on the packaging of (pre-) genomic RNA and identified two distinct signals within the cis-acting sequences (CASI and CASII), Pol encapsidation sequences (PESI and PESII), which are required for Pol capsid incorporation. Here, we investigated whether the presence of PESI and PESII in an FV vector is sufficient for Pol encapsidation and whether the rather extended CASII element can be shortened without loss of functionality. Our results indicate that (i) the presence of PESI and II are not sufficient for Pol encapsidation, (ii) prototype FV vectors with a shortened CASII element retain Pol incorporation and full functionality, in particular upon transducing fibroblasts and primary human mesenchymal stem cells, (iii) the presence of the central poly purine tract significantly increased the transduction rates of FV vectors and (iv) Pol encapsidation and RNA packaging can be clearly separated. In essence, we designed a new FV vector that bears approximately 850 bp less of CAS than previously established vectors and is fully functional when analysed to transduce cell lines and primary human cells.
authors.affiliation: Universität Würzburg, Institut für Virologie und Immunbiologie, Würzburg, Germany.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Wiktorowicz
authors.affiliation: University of California, International Laboratory of Molecular Biology for Tropical Disease Agents, School of Veterinary Medicine, Davis, USA.|Universität Würzburg, Institut für Virologie und Immunbiologie, Würzburg, Germany.
authors.forename: Katrin
authors.initials: K
authors.lastname: Peters
authors.affiliation: Universität Würzburg, Orthopaedic Center for Musculoskeletal Research, Orthopaedic Clinic König-Ludwig-Haus, Würzburg, Germany.|Universität Würzburg, Institut für Virologie und Immunbiologie, Würzburg, Germany.
authors.forename: Nicole
authors.initials: N
authors.lastname: Armbruster
authors.affiliation: Universität Würzburg, Orthopaedic Center for Musculoskeletal Research, Orthopaedic Clinic König-Ludwig-Haus, Würzburg, Germany.
authors.forename: Andre F
authors.initials: AF
authors.lastname: Steinert
authors.affiliation: Universität Würzburg, Institut für Virologie und Immunbiologie, Würzburg, Germany.
authors.forename: Axel
authors.initials: A
authors.lastname: Rethwilm
mesh_terms: D002213:Capsid / Q000378:metabolism; D036022:Capsid Proteins / Q000235:genetics; D002460:Cell Line; D017931:DNA Primers; D015684:Gene Products, pol / Q000235:genetics*; D005822:Genetic Vectors; D016679:Genome, Viral; D006801:Humans; D007668:Kidney; D016366:Open Reading Frames; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics; D012367:RNA, Viral / Q000235:genetics; D016092:Spumavirus / Q000235:genetics* / Q000502:physiology; D014162:Transfection; D014779:Virus Replication
chemical_list: D036022:Capsid Proteins; D017931:DNA Primers; D015684:Gene Products, pol; D012333:RNA, Messenger; D012367:RNA, Viral