N-myc activation by proviral insertion in MCF 247-induced murine T-cell lymphomas.

N-myc proto-oncogene rearrangement was found in three out of six AKR murine T-cell lymphomas induced by the highly oncogenic MCF 247 MuLV. Molecular analyses showed that structural modification of the proto-oncogene in all three lymphomas was in the consequence of MCF 247 proviral integration within the gene III exon. All integrated proviruses have the same transcriptional orientation as the N-myc gene. As a consequence of proviral insertion, the N-myc gene becomes transcriptionally active, producing an abnormal mRNA. These findings suggest a possible causative role of such an integrative event in murine T-cell lymphomagenesis.