PATHWAYS OF NUCLEIC ACID SYNTHESIS. Progress Report . February 1, 1960- January 31, 1961

Technical Report · Wed Feb 15 04:00:00 EST 1961

OSTI ID:4041028

Abrams, R

On the assumption that the cell nucleus is a major site of RNA synthesis, enzyme systems involved in polynucleotide synthesis in this organelle were investigated. An enzyme was isolated which is specific for CTP incorporation. The enzyme was resolved into specific RNA primer components and a protein component. The primers are not interchangeable. Priming of the ATP polymerization was investigated in some detail with various nucleases. The data suggest that the natural primer is either a polyadenylic acid or a polynucleotide containing as its active portion a sequence of adenylate units. Thus poly A can prime the reaction, while the natural primer is resistant to pancreatic RNase and takadiastase-T/sub 1/ RNase but destroyed by squid RNase. The CTP enzyme preparation carries out both internal and terminal incorporation, and the data suggest these may represent two separate enzymes. The physiological role of these enzymes is still obscure. A particulate system obtained after homogenizing calf thymus nuclei and extracting the residue exhaustively with Tris buffers was also investigated. The particulate residue incorporates nucleoside triphosphates into RNA only if all four triphosphates are present. The composition of the newly formed RNA resembles that of nuclear RNA more closely than that of DNA. The preparation contains protein, RNA, and DNA in a ratio of 1: 0.3: 3.0. The RNA is essential for the incorporation reaction since the particles are inactivated by treatment with squid RNase and the activity restored by addition of its own RNA. The role of DNA is uncertain. Treatment with DNase inhibits the reaction, but efforts to restore activity with added DNA failed. Incubation at 37 deg results in transfer of RNA from the particles to the soluble phase. The possible significance of this reaction in transfer of genetic information merits further study. Results are also reported from a study of the mechanism whereby guanine is converted to hypoxanthine in rat liver extracts. Results indicate that the reaction occurs at the free base level, the pathway involving deamination by guanase to xanthine, re duction by DPNH and xanthine oxidase to hypoxanthine, and stabilization at the hypoxanthine oxidation level by conversion to inosine in the presence of nucleoside phosphorylase. (auth)

• Research Organization: Montefiore Hospital. Inst. of Research, Pittsburgh
• NSA Number: NSA-15-015378
• OSTI ID: 4041028
• Report Number(s): TID-11940
• Country of Publication: United States
• Language: English

Related Subjects

BIOLOGY AND MEDICINE
CHEMICAL REACTIONS
ENZYMES
GENETICS
GLANDS
LIVER
NUCLEIC ACIDS
PANCREAS
PHOSPHATES
PHYSIOLOGY
PROTEINS
RATS