Strategy for the ablation of p12, p30, and HBZ and characterization of the mutant viruses and cell lines. (A) Genetic organization of the HTLV-1 provirus genome and schematic representation of the overlapping orf I-IV (top). Amino acid changes in the mutant molecular clones (bottom). LTR indicates long terminal repeat. (B) Level of p19 Gag produced in the supernatants of the 729 B cell–infected cell lines measured by enzyme-linked immunoabsorbent assay. (C) Western blot analysis of the cell lysates from the 729 B-cell lines infected with the HTLV-1 mutant viruses with the use of antibodies to p24 Gag and to Tax. An antibody to tubulin was used as a control for equal loading of proteins. (D) Southern blot analysis of genomic DNA from the infected 729 B-cell lines. The numbers on the right represent the migration of the molecular weight (MW) marker.