Introduction of the 5-halogenated uracil moiety into deoxyribonucleic acid of mammalian cells in culture.

Introduction of the 5-halogenated uracil moiety into the deoxyribonucleic acid of several bacterial strains has been described by Weygand and Wacker (l), Zamenhof and Griboff (2), and Dunn and Smith (3). A corresponding introduction into the deoxyribonucleic acid of mammalian cells was recently reported by Eidinoff et al. (4, 5, 6) and by Prusoff (7) when 5-bromodeoxyuridine or 5-iododeoxyuridine was supplied in vitro or in viva. The studies reported below demonstrate eytensive introduction of the unnatural base into the DNA of six mammalian cell strains when 5-bromodeoxyuridine or 5iododeoxyuridine is added to the normal culture medium. Growth inhibition by these compounds of H.Ep. No. 1 cells, a strain derived from a human cervical carcinoma (8), has also been studied.