FIG. 5.

Host DNA sequence flanking integrated viral DNA from virus encoding mutant IN protein is not random. Shown is the frequency of each nucleotide in the host DNA at the five positions immediately flanking the 3′ end of each strand of DNA. That is, the host DNA sequence is adjacent to the top strand of viral DNA on the right but from the bottom strand of viral DNA on the left. This contrasts with Fig. 3, in which both the right and the left flanking host DNA sequences are adjacent to the top strand of the integrated viral DNA. For sequence to the left of the provirus, host DNA at −1 is immediately adjacent to the provirus and −5 is located 5 bp from the provirus; for the right side, host DNA at +1 is immediately adjacent to the provirus and +5 is located 5 bp from the provirus. A host G residue is disproportionately represented immediately flanking each end of the provirus, and there is a tendency for a T at positions −2 and +2.