[Activation of N-myc gene in leukemia cell lines derived from spontaneous murine lymphomas].

MuLV-integration sites were analyzed on seventeen thymic leukemia cell lines which have been established from spontaneous thymic leukemias in AKR mice and bone marrow chimeras. Three proviral integration sites were identified; near c-myc, N-myc and pim-1. Among them the integrations near the N-myc were analyzed. Two cell lines from AKR and a cell line from [(BALB/c x B6) F1-->AKR] bone marrow chimera contained the proviral integration near N-myc. In all three cell lines the integration of the provirus was found 18 to 20 bp downstream of the translational termination codon. The partial sequence analysis of the integrated LTR cell line established from AKR thymic lymphomas was the same as AKV. In contrast, the LTR integrated in a cell line from a bone marrow chimera was different from that of MuLV so far reported.