Oncogenic retrovirus from spontaneous murine osteomas. II. Molecular cloning and genomic characterization.

An N-ecotropic murine leukemia virus (OA MuLV), originally isolated from spontaneous osteomas of strain 101 mice, was molecularly cloned. The virus induces osteomas, osteopetrosis, and malignant lymphomas in NMRI mice. The cloned virus was analyzed by heteroduplex analysis, restriction enzyme mapping, and oligonucleotide mapping. The data show a very close relationship to the endogenous Akv prototype virus with some differences in the gag and the env region. The nucleotide sequence of the U3 region of OA MuLV LTR revealed a structure within the presumable enhancer region very similar to the U3 sequences of the FBJ murine sarcoma virus and its associated helper virus. The significance of these specific structures for the oncogenicity of the virus and the development of the typical disease pattern is discussed.