Cellular DNA region involved in induction of thymic lymphomas (Mlvi-2) maps to mouse chromosome 15.

Two cellular DNA regions representing common domains for proviral DNA integration ( Mlvi -1 and Mlvi -2) have been identified in Moloney murine leukemia virus-induced rat thymic lymphomas. Cellular sequences which were free of repeated DNA derived from a clone that defines the Mlvi -2 integration domain (lambda Cl228 ) were found to be highly conserved in a variety of vertebrate species that we examined, including mice, hamsters, cats, and humans. In this study, we identified the chromosomal map location of the Mlvi -2 homologous sequences in mice by using hamster-mouse somatic cell hybrids. The results show that Mlvi -2 is present on mouse chromosome 15 but is unrelated to the c-myc and c-sis proto-oncogenes, which map on the same chromosome. Since aberrations on chromosome 15 have been observed reproducibly in mouse thymomas, our data suggest that Mlvi -2 may define a novel sequence involved in the induction or progression of murine thymic lymphomas.