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. Author manuscript; available in PMC: 2019 Jul 6.
Published in final edited form as: J Mol Biol. 2018 May 19;430(14):2066–2079. doi: 10.1016/j.jmb.2018.05.029

Figure 4.

Figure 4

Context effects of minimal packaging elements on the packaging of a heterologous RNA. (A) Schematic representation of HIV-1 derived test vectors for study of effects of lacZ sequence on packaging. (B) RNase protection assay of samples obtained from co-expression of test vectors with a Ψ+ helper. Cell RNA samples are at left and virus RNA is in the right panel. Riboprobe E, which is a chimeric riboprobe that includes sequences complementary to both gag and lacZ (see Materials and Methods), was used in these experiments. Protected riboprobe fragments corresponding to test (Vector) and helper (Ψ+ Helper) RNAs are indicated. Lane labels indicate the vectors that were co-expressed with Ψ+ helper. Ψ+ helper alone; mock: mock transfected cells; tRNA: riboprobe protected with yeast tRNA; M: molecular weights marker; P: undigested probe. (C) Quantification of packaging efficiency of HIV-1 vectors. The packaging efficiency was calculated by dividing the ratio of vector RNA to helper RNA in the virion by the ratio of vector RNA to helper RNA in the cells as determined by RNase protection analysis and quantified by phosphorimager analysis. The results represent data from at least three independent transfection experiments.