Figure 1.

Construction of the recombinant full-length Pr77^Gag bacterial expression vector. (A) Domain organization of the mouse mammary tumor virus (MMTV) Gag precursor with His₆-tag; (B) Nucleic acid and amino acid sequences of full-length MMTV gag gene. An internal NcoI site (boxed in blue color) was removed by introducing a silent mutation (shown in the inset) that preserved the threonine (Thr) amino acid. The Shine-Dalgarno-like sequence and second in-frame ATG are highlighted by green color; (C) Schematic representation of bacterial expression plasmid AK1 containing full-length MMTV Pr77^Gag gene cloned into the NcoI and XhoI sites of the pET28b(+) vector.