Human foamy virus integrase fails to catalyse the integration of a circular DNA molecule containing an LTR junction sequence.
The presence of closed circular forms of the linear DNA genome of human foamy virus (HFV) has not been established. The ability of the HFV integrase (IN) to catalyse the integration of these circular forms (termed 2 long terminal repeat (LTR) circles) was investigated, with a view to producing a novel hybrid vector. To this end, a construct was made containing, in addition to the enhanced green fluorescent protein (eGFP) marker gene, the last 27 bp of the 3' U5 LTR region of HFV fused to the first 28 bp of the 5' U3 LTR, the latter representing a 2LTR circle. Marker gene expression following transfection of both 293 and 293T cells indicated that the level of integration was not significantly increased by the HFV IN. Moreover, correctly integrated provirus-like forms of the input plasmid could not be detected by PCR. Taken together, these results show that the HFV IN is not able to integrate a circular molecule containing an LTR junction and, hence, the technique is not exploitable as a tool to produce hybrid vectors for gene therapy.
Russell
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RA
Jefferiss Research Trust Laboratories, Wright-Fleming Institute, Imperial College School of Medicine at St Mary's Hospital, Norfolk Place, London W2 1PG, UK.
Critchley
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R
Vassaux
G
G
McClure
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MO
D002384:Catalysis; D004270:DNA, Circular / Q000235:genetics*; D004279:DNA, Viral / Q000235:genetics; D005819:Genetic Markers; D005822:Genetic Vectors; D006801:Humans; D019426:Integrases / Q000737:chemistry / Q000378:metabolism*; D016092:Spumavirus / Q000201:enzymology*; D020079:Terminal Repeat Sequences / Q000235:genetics*; D014162:Transfection; D016662:Virus Integration
D004270:DNA, Circular; D004279:DNA, Viral; D005819:Genetic Markers; D019426:Integrases