Project Title: 17. Molecular and Cellular Radiobiology The Chemistry and Function of DNA Polymerases Expected Results in FY 1974: (Cont'd.) RK -03-02- (a) carried out on a sufficient number of samples to be sure chat the results, either positive or negative, are reliable. If incorporation into 705 particles is found, the incorporated activity will be examined in the ultracentrifuge by isopycnic banding to see if it is in a particle of density approximately 1.16 g/cc (characteristic of a virus). The incorporated activity will also be examined by established hybridization techniques to determine whether or not it is complementary to any of the known and obtainable oncogenic viruses. Finally, the various samples under study will be examined in che electron microscope for the presence of virus-like particles. Progress in the study of hybridization of I-125 labeled viral RNA to cellular DNA will depend on how much time Dr. Prensky can devote to it. It is anticipated that at least one complete study can be made, ably involve the interaction of Murine Leukemia Virus ThiS will prob- (Rauscher) with BALB/c mouse bone marrow cells, 18. Expected Results in FY 1975: Although the study of the hybrid template-dependent DNA synthesis in chick embryo tissues has not progressed as fast as was anticipated a year ago, it is reasonable to expect that purification of the enzyme involved will be completed during the coming year. Since the mechanism of DNA replication’ in eukaryotic cells is still very obscure, the role of this particular enzyme in the cell's economy still requires investigation, The ability to prepare a specific antibody to the purified enzyme should facilitate this study, this area of research, In the outlook changes so rapidly that it is difficult fo predict what the emphasis will be a year or two from now, The studies proposed on radiation-induced mammary tumors will probably require more than one year, If the presence of type B or C particles in these radiation-induced tumors is established, animals which have been irradiated -- or treated with chemical carcinogens-~-—will be examined to determine whether particles are present prior to the appearance of detectable tumors, If a careful search fails to show the presence of virus-like particles in these rat tumors, the studies will terminate. ot 19. Studies on virus RNA hybridization will be extended to other viruses and y-cell lines to see if some generalizations can be made, Recription and Explanation of Major Materials, Equipment and -Subcontract Items: FY 1975 Capital Equipment: A high capacity preparative ultracentrifuge is necessary for large scale preparations of viruses, and will be used in other research activities Corad, Wetbale pa Tits (See Continuation Sheet) [119282 RX- 222