APPENDIX B 
4 
1973; Shah, K. V., Daniel, R. W. and Strandberg, J., J. Nat. Cancer Inst. 
54 , 945-950, 1975); BK virus causes transformation of hamster cells in 
culture (Major, E.D., and DiMayorca, G., Proc. Nat. Acad. Sci. US, 70, 
3210-3212, 1973; Portolani, M., Barbanti , A., Brodano, G. and LaPlaca, 
M.J., Virol. 1_5, 420-422, 1975) and is able to complement the growth of 
certain temperature-sensitive mutants of SV40 (Masion, B. H. and Takemoto, 
K. K., submitted for publication). 
Further Work 
At present, a potential eukaryotic vector of choice is polyoma virus. 
And while available information indicates that it fulfills all the necessary 
criteria, we recommend that the following subjects be further investigated: 
1. The molecular mechanism of resistance of human cells to the virus. 
2. The extent of homology between polyoma virus DNA and the DNAs of 
human papovavi ruses . 
3. The ability of human papovaviruses to complement defective polyoma 
virus genomes. 
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