Detection of RNA-instructed DNA polymerase and high molecular weight RNA in malignant tissue

An experimental procedure is detailed that permits the detection of 70S RNA-directed DNA synthesis in mouse mammary carcinomas. The DNA synthesized is complementary to the RNA of the mouse mammary tumor virus by molecular hybridization, thus, completing the proof that an RNA-instructed DNA polymerase has been identified. Further, RNA-instructed DNA polymerase and its 70S RNA template are physically associated in a particle that has a density characteristic of oncornaviruses. These experiments now provide the technology required to perform similar examinations of human neoplasias.