Molecular structure of canine LINE-1 elements in canine transmissible venereal tumor

We determined the 4251-bp sequence of open reading frame 2 (ORF2) of canine LINE-1 retroposon that encodes 1275 amino acids. The truncated LINE-1 inse rts associated with transmissible venereal tumor (TVT) of dogs contained th e 1378-bp LINE-1 insert (TVT-LINE) flanked by 10-bp direct repeats upstream to myc gene. The TVT-LINE elements were composed of 416 bp inverse sequenc es homologous to the complementary strand of the LINE-1, a 5-bp deletion an d 962-bp sequences homologous to the 3' region of the LINE-1.