Showing papers by "Michael B. Sporn published in 1967"

The Binding of Metabolites of Aminoazo Dyes to Rat Liver DNA in Vivo

Abstract: Summary The binding of isotopically labeled aminoazo dye metabolites to rat liver DNA and protein in vivo was investigated. Both benzenoid ring systems of 4-dimethylaminoazobenzene (DAB) bind to DNA. When rats were prefed a high riboflavin diet (which inhibits carcinogenesis by DAB), less binding of DAB metabolites to both DNA and protein was observed. However, the inhibition of binding to DNA resulting from a high riboflavin diet was significantly greater than the inhibition of binding to protein. The binding of metabolites of the carcinogenic aminoazo dye 3′-methyl-4-dimethylaminoazobenzene to DNA in vivo was found to be 6 times greater than that observed with the noncarcinogenic dye 2-methyl-4-dimethylaminoazobenzene and 9 times greater than that observed with another noncarcinogenic dye, 3′-trifluoromethyl-4-dimethylaminoazobenzene. These findings support the proposal that binding to DNA by a compound may be necessary to initiate carcinogenesis.

Purification of T antigen from nuclei of simian virus 40-induced hamster tumors.

Abstract: We report here the extensive purification of the simian virus 40 (SV40) T antigen (virus-induced complement-fixing antigen, tumor neoantigen) from nuclei of transplanted, virus-free hamster tumors originally induced by SV40 virus. The cellular function of this protein or group of proteins is presently unknown. Purification of this material may lead to further definition of its role. Gilden et al. (Proc. Natl. Acad. Sci. U.S. 53:684, 1965) have previously reported the preliminary purification of T antigen and its sedimentation pattern in sucrose density gradients. SV40 fibrosarcomas were serially passaged in golden hamsters approximately every month in