FIG. 3.

Analysis of proviral U3 regions in tumor DNAs. (A) PCR amplification of U3 enhancer sequences of DNA of Akv- and Akv1- 99-induced tumors; the numbers refer to the animal numbers presented in Table 2. M, DNA size markers. The positions of amplified fragments resulting from Akv (positions 12 to 375) and Akv1- 99 (positions 12 to 276) are shown. (B) Akv and Akv1- 99 U3 structures showing the PCR primers used in panel A. Below is shown the input Akv1- 99 sequence (positions 40 to 258). (C) All nucleotide sequences of PCR fragments of Akv1- 99-induced tumors were determined from positions corresponding to 40 to 258 of the input U3 sequence shown in panel A. Only tumor 10 showed changes as shown in the lower band.