SEQUENCE TAGS OF PROVIRUS INTEGRATION SITES IN DNAS OF TUMORS INDUCEDBY THE MURINE RETROVIRUS SL3-3

The murine retrovirus SL3-3 is a potent inducer of T-cell lymphomas wh en inoculated into susceptible newborn mice. The proviral integration site sequences were surveyed in tumor DNAs by a simple two-step PCR me thod, From 20 SL3-3-induced tumors a total of 39 provirus-host junctio ns were amplified and sequenced, Seven showed homology to known sequen ces. These included the known common integration site c-myc as well as genes not previously identified as targets of provirus integration, n amely N-ras and the genes coding for major histocompatibility complex class II 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 integrat ion site sequences that show no similarities to known sequences may re present a common integration site, as 2 of the 20 tumors demonstrated clonal provirus insertion into this region.