MusD gene products required for retrotransposition. (A) Assay for MusD retrotransposition was performed as in Figure 3, with either the wild-type neoTNF marked MusD-6 (WT) or the same element rendered defective for gag or pro (via an in-frame deletion in the corresponding gene so as not to alter translation of the downstream ORFs) or pol (via an out-of-frame deletion). The retrotransposition frequencies obtained for each construct are indicated. (B) Western blot analysis for cleavage of the MusD Gag polyprotein. Lysates of cells transfected with a control plasmid (mock) or the MusD constructs in A were electrophoresed (SDS-PAGE), blotted, and hybridized with a rabbit anti-serum directed against the Gag polyprotein. The apparent molecular mass for the major bands of the wild-type MusD is indicated.
