Project Title: L5, Molecular and Cellular Radiobiology Storage and Transfer or the Genetic Message Relationship to Other Projects: RX-03-02-(d) (Cont'd.) of transfer RNA's, Studies on protein synthesis are being made by Nirenberg, NIH, Bethesda; Lipmann and associates at Rockefeller University; and Ochoa and co-workers at New York University. Watson at Harvard and Cold Springs Harbor; Jacob and Monod at Pasteur Institute; Fraenkel-Conrat and Singer, University of California, Berkeley; and Spiegelman at Institute for Cancer Research, Columbia University, are studying the transfer of information by messenger RNA, its relation to DNA and ribosomes and the interaction of various polynucleotides. Research on DNA- RNA hybrids is being done by Hayashi at La Jolla, Konrad at Berkeley, and Spiegelman; they have examined virus infected cells for such hybrids with conflicting results, N + Baltimore at MIT and Temin at McArdle Laboratory for Cancer Research, Wisconsin, have found an RNA-dependent polymerase in virions of RNA tumor viruses, They, and now many others, are studying this problem, which has implications not only for oncogenesis by RNA viruses, but also for the general understanding of genetic transcription, Similar studies are being made by Spiegelman who has also described a DNA-directed DNA polymerase be- sides the RNA-dependent DNA polymerase activity possessed by oncogenic RNA viruses, This DNA-directed polymerase prefers double-stranded RNA as template and yields a principally double-stranded product, Gallo at NCI-NIH has described an RNA-dependent DNA polymerase in human acute leukemic cells, and _ Cavalieri has described how 5S and ribosomal RNA's can serve as primers for DNA synthesis using a DNA polymerase from E, coli, Crippa at the CNR Laboratory of Molecular Embryology, Arco Felice and Tocchini-Valentini at CNR Institute of Genetics and Biophysics, Naples, have described data in oocytes of Xenopus laevis consistent with the hypothesis that RNA-dependent synthesis is a way of amplifying ribosomal genes in the egg. etc,, - Other physico-chemical studies, e.g, temperature- jump, melting curves, to determine sequence complementary on nucleic acids are made by Doty at Harvard and on transfer RNA's by Berg at Stanford. The Setlows at Oak Ridge National Laboratory are studying enzymes that repair DNA after damage, and Freifelder at Brandeis, the nature of the lethal lesion in DNA after radiation injury, genetic recombination. Increasing evidence from many laboratories is pin-pointing the nucleic acids as key targets of radiation damage as reported by the Setlows, K, Smith at Stanford, Howard-Flanders at Yale, M. Omerod at Chester Beatty, J. Lett at Colorado State. The effects of polynucleotides and of other interferon-inducers, especially the anti-viral and anti-tumor effects are studied by Field, Tytell, Lampson, and Hilleman at the Merck Institute, Baron and Levy at NIH, Merigan at Stanford, and Chamberlain at Berkeley. (See Continuation Sheet) 1149312 Hillman, Baron, Levy, RX- 252