FIG. 4.

Three types of proviruses. (A) Normal provirus; (B) provirus with an aberrant integration at the U5 LTR terminus. Deletions in U5 are indicated by a black jagged end. Target duplications (a long black arrow) or deletions (no arrow) are indicated (see the legend to Fig. 5 for details). (C) Proviruses with complex structures. Deletions or insertions in U5 are indicated by a white box with black horizontal bars. Additional insertions of other viral sequences or host genome are shown with a white arrow. The direction of the arrowhead indicates the orientation of the extra viral sequences relative to the viral genome. Large duplications of host DNA are indicated by a long black arrow. The direction of the arrow corresponds to the numbering of the host genomic DNA. Ch., chromosome.