Bovine leukosis virus: recloning of specific DNA fragments

DNA fragments generated by Bam HI restriction endonuclease digestion of the provirus of bovine leukosis virus (BLV) was recloned in several plasmids. Recombinant plasmids containing X-region, env gene and a part of pol gene were prepared in pBR322, and in a plasmid containing promotor PR. Fragments env gene and a part of pol gene inserted were also into the pSV2-dhfr plasmid which has the both bacterial and eukaryotic promotors together with the gene for folic acid reductase. The expression possibility of these inserted BLV sequences either in mammalian cells after transfection or in bacteria is now tested.