Identification of a DNA fragment from a molecularly cloned mink cell focus-inducing murine leukemia virus specific for xenotropic virus-related sequences.

Molecular clones of closed circular DNA molecules of a mink cell focus-inducing murine leukemia virus (MCF-13 MuLV) were generated. Closed circular DNA molecules isolated from a Hirt extraction of recently infected NIH/3T3 cells were inserted at their unique EcoRI site into lambda gtWES.lambda B. Restriction endonuclease analysis of inserts of two clones indicated that they represented intact MCF-13 MuLV genomes. One viral insert contained two large terminal repeat sequences, and the other contained only one. A 300-base-pair DNA fragment located in the envelope region of the MCF-13 MuLV genome was determined to be related to xenotropic MuLV sequences.