The induction of tumors in the hybrid Nicotiana glauca x N. langsdorffii plants by 6-azauracil and its reversal by uracil and actinomycin D.

Azauracil was found to be the only one of several analogs of nucleic acid precursors tested in these studies which is capable of inducing tumors at a very early stage during seedling development in the genetically tumor-conditioned hybrid Nicotiana glauca • N. Iangsdorffii. Tumor induction by 6-azauracil was shown to be reversed by simultaneous treatments with uracil and actinomycin D as well as by posttreatments. Pretreatments with the same substances proved to be ineffective. The possible implications of the findings in view of the possible involvement of an abnormal species of RNA in the process of tumor induction by 6-azauracil are discussed.