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. 2002 Dec 15;30(24):e142. doi: 10.1093/nar/gnf142

Figure 2.

Figure 2

Comparative levels of expression for pEYK retroviral vectors. (A) FACS plots of BaF/3 cells infected with pMX, pEYK2, pEYK2.1 and pEYK3.1 retroviral vectors demonstrate differences in GFP fluorescence (pEYK1 was not included in the overlay to allow better visualization of profiles for other vectors). Expression levels were calculated as fold-increase in geometric mean fluorescence above background fluorescence, and represent averages of triplicate infections with standard deviations. Mutagenesis of the two internal ATGs (**) within the gag region of pMX yielded pEYK2, which showed modest but consistent increases in GFP expression over pMX. This enhanced packaging region was incorporated into the pEYK2.1 and pEYK3.1 vectors. (B) FACS plots of BaF/3 cells infected with pEYK3 and pEYK3.1 demonstrate a 4-fold increase in expression levels with the incorporation of the mutagenized gag sequences into pEYK3.1. The pEYK3 vector lacks the mutagenized gag sequence. For both plots, GFP expression is measured on a logarithmic scale.