[Mapping of "nonessential" regions in the genome of vaccinia virus].

The special molecular probe for mapping the "nonessential" regions in the genome of vaccinia virus has been obtained by the genetic engineering methods. The probe included the gene for beta-galactosidase of E. coli under the control of vaccinia virus 7.5 K protein promoter as well as the gene for kanamycin resistance. In its final version the probe is obtainable from the plasmid pUCZ beta using the restriction endonucleases SalI, BamHI, EcoRI. The probe included by the BamHI fragment of DNA was inserted into the HindIII-E-fragment of the vaccinia virus (cloned into a plasmid) in 8 of the existing 9 BglII cleavage sites. The latter plasmids were introduced into the chicken embryo cells infected by the vaccinia virus. The plasmid having the probe inserted into the 5th BglII site (from the left end) of the HindIII-E fragment permitted to obtain the live vaccinia strain expressing the beta-galactosidase. Thus, the "nonessential" region of vaccinia virus, that was not described previously, is mapped.