Figure 1
(a) Schematic representation of a simplistic model of retroviral genomic RNA packaging. The presence of an intact RNA secondary structure of the packaging signal (psi; ψ) facilitates genomic RNA packaging, whereas loss of its structure in the spliced RNA excludes its packaging. (b) Illustration of the MPMV Gag proteins expressed from the prokaryotic expression vector either with (FN1) or without (FN1A) the His6-tag (6xH). The amino acid residues LE were introduced upstream of the His6-tag into the FN1 vector during the cloning process.
