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. Author manuscript; available in PMC: 2011 Aug 26.
Published in final edited form as: Gene Ther. 2009 Sep 10;17(1):37–49. doi: 10.1038/gt.2009.118

Figure 2. Improved FV helper constructs.

Figure 2

A map of the wt HFV infectious clone pHSRV13 is shown above the foamy Gag, Pol and Env helper constructs that were generated by high-fidelity PCR from the wt HFV plasmid pHSRV13. To eliminate overlap between the Gag and Pol helper plasmids the carboxyl terminus 259 codons of the Gag ORF was replaced with a codon-optimized (CO) sequence (indicated by stripes) to create the pFV-GagCO helper plasmid. The overlap between the pFV-Pol and pFV-Env helper plasmids was reduced to only 31 bp of 100% identity by incorporating a total of four silent mutations indicated by crosses in the expanded view of the overlap between pol and env. All 3 foamy helper plasmids are driven by a cytomegalovirus (CMV) promoter. LTR is long terminal repeat. The foamy accessory proteins Tas (foamy transcriptional transactivator) and Bet are not present in the replication-incompetent FV vector system.