Improved primate foamy virus vectors and packaging constructs.
Foamy virus (FV) vectors that have minimal cis-acting sequences and are devoid of residual viral gene expression were constructed and analyzed by using a packaging system based on transient cotransfection of vector and different packaging plasmids. Previous studies indicated (i) that FV gag gene expression requires the presence of the R region of the long terminal repeat and (ii) that RNA from packaging constructs is efficiently incorporated into vector particles. Mutants with changes in major 5' splice donor (SD) site located in the R region identified this sequence element as responsible for regulating gag gene expression by an unidentified mechanism. Replacement of the FV 5' SD with heterologous splice sites enabled expression of the gag and pol genes. The incorporation of nonvector RNA into vector particles could be reduced to barely detectable levels with constructs in which the human immunodeficiency virus 5' SD or an unrelated intron sequence was substituted for the FV 5' untranslated region and in which gag expression and pol expression were separated on two different plasmids. By this strategy, efficient vector transfer was achieved with constructs that have minimal genetic overlap.
Heinkelein
Martin
M
Institut für Virologie und Immunbiologie, Universität Würzburg, Germany.
Dressler
Marco
M
Jármy
Gergely
G
Rammling
Matthias
M
Imrich
Horst
H
Thurow
Jana
J
Lindemann
Dirk
D
Rethwilm
Axel
A
D020121:5' Untranslated Regions / Q000235:genetics; D000818:Animals; D002460:Cell Line; D015683:Gene Products, gag / Q000235:genetics / Q000378:metabolism; D015684:Gene Products, pol / Q000235:genetics / Q000378:metabolism; D005822:Genetic Vectors; D006801:Humans; D010957:Plasmids / Q000235:genetics; D011323:Primates; D012367:RNA, Viral / Q000378:metabolism; D016092:Spumavirus / Q000235:genetics*; D019065:Virus Assembly
D020121:5' Untranslated Regions; D015683:Gene Products, gag; D015684:Gene Products, pol; D012367:RNA, Viral