Extensive homology of nuclear ribonucleic acid and polysomal poly(adenylic acid) messenger ribonucleic acid between normal and neoplastically transformed cells.

A cell line, designated BP6T, derived from Syrian hamster embryo (SHE) cells following treatment with benzo[a]pyrene is capable of producing tumors in newborn hamsters following the injection of as few as 1-10 cells. Polysomal poly(A) mRNA and total nuclear RNA obtained from this highly tumorigenic cell line were compared to RNAs obtained from the nonneoplastic parental embryo cells by a variety of techniques. RNA excess hybridizations to normal cell radiolabeled single-copy DNA or to a single-copy DNA tracer enriched for sequences transcribed in neoplastically transformed cells were unable to detect any significant differences in RNA sequence complexity between normal SHE cells and neoplastic BP6T cells. This finding of extensive homology of polysomal poly(A) mRNA and total nuclear RNA between normal and neoplastic cells, together with our previous finding of extensive homology of the major 35S-labeled nuclear or cytoplasmic polypeptides observable on two-dimensional gels [Leavitt, J. C., & Moyzis, R. K. (1978) J. Biol. Chem. 253, 2497-2500], demonstrates that the phenotypic changes associated with neoplastic transformation by chemical carcinogens are accompanied by relatively few changes in the qualitative pattern of gene expression in cells cultured in vitro.