Sequence tags of provirus integration sites in DNAs of tumors induced by the murine retrovirus SL3-3.

The murine retrovirus SL3-3 is a potent inducer of T-cell lymphomas when inoculated into susceptible newborn mice. The proviral integration site sequences were surveyed in tumor DNAs by a simple two-step PCR method. From 20 SL3-3-induced tumors a total of 39 provirus-host junctions were amplified and sequenced. Seven showed homology to known sequences. These included the known common integration site c-myc as well as genes not previously identified as targets of provirus integration, namely N-ras and the genes coding for major histocompatibility complex class 11 E-beta, protein kinase C-eta, and T-cell receptor beta-chain. Among these genes, the integrations in c-myc as well as the one in N-ras were found to be clonal. One of the remaining 32 proviral integration site sequences that show no similarities to known sequences may represent a common integration site, as 2 of the 20 tumors demonstrated clonal provirus insertion into this region.