Dr. Adams has purified two mRNAs during the previous grant period. During the new grant period, he plans to: 1) determine the exact nature of several mRNAs; 2) localize methylated nucleosides elsewhere within mRNA; 3) compare modified nucleotides and 5'-terminal end groups in heterogeneous nuclear RNA and cytoplasmic mRNA; 4) complete purification of at least one light chain mRNA and other studies on it; 5) synthesis of DNA complementary to portions of a purified light chain mRNA (cDNA) using an enzyme with reverse transcriptase activity; 6) transcription of this cDNA molecule to a cRNA; and 7) employ these molecules as probes in hybridization experiments to localize and quantitate specific DNA and RNA. BIBLIOGRAPHIC REFERENCES: Cory, Suzanne and J. M. Adams. The Modified 5'-Terminal Sequences in Messenger RNA of Mouse Myeloma Cells. J. Mol. Biol. 99. 519-547, (1975). Cory, S. and J. M. Adams. Modified 5'-Termini in Small Nuclear RNAs of Mouse Myeloma Cells. Molecular Biology Reports 2, 287-294, (1975).